78147540 has 72 divisors (see below), whose sum is σ = 238853160. Its totient is φ = 20680704.

The previous prime is 78147533. The next prime is 78147541. The reversal of 78147540 is 4574187.

78147540 is a `hidden beast` number, since 78 + 1 + 47 + 540 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 20903184 + 57244356 = 4572^2 + 7566^2 .

It is a super-2 number, since 2×78147540² = 12214076016103200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 78147495 and 78147504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78147541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23076 + ... + 26244.

It is an arithmetic number, because the mean of its divisors is an integer number (3317405).

Almost surely, 2^78147540 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78147540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119426580).

78147540 is an abundant number, since it is smaller than the sum of its proper divisors (160705620).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78147540 is a wasteful number, since it uses less digits than its factorization.

78147540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3321 (or 3316 counting only the distinct ones).

The product of its (nonzero) digits is 31360, while the sum is 36.

The square root of 78147540 is about 8840.1097278258. The cubic root of 78147540 is about 427.5350950977.

It can be divided in two parts, 78147 and 540, that added together give a palindrome (78687).

The spelling of 78147540 in words is "seventy-eight million, one hundred forty-seven thousand, five hundred forty".