78172542 has 72 divisors (see below), whose sum is σ = 198362736. Its totient is φ = 22184064.

The previous prime is 78172541. The next prime is 78172553. The reversal of 78172542 is 24527187.

It is a super-2 number, since 2×78172542² = 12221892645483528, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 78172497 and 78172506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78172541) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 231798 + ... + 232134.

It is an arithmetic number, because the mean of its divisors is an integer number (2755038).

Almost surely, 2^78172542 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78172542, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99181368).

78172542 is an abundant number, since it is smaller than the sum of its proper divisors (120190194).

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

78172542 is a wasteful number, since it uses less digits than its factorization.

78172542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 622 (or 612 counting only the distinct ones).

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

The square root of 78172542 is about 8841.5237374561. The cubic root of 78172542 is about 427.5806844735.

The spelling of 78172542 in words is "seventy-eight million, one hundred seventy-two thousand, five hundred forty-two".