78105780 has 72 divisors (see below), whose sum is σ = 237734952. Its totient is φ = 20756736.

The previous prime is 78105767. The next prime is 78105791. The reversal of 78105780 is 8750187.

78105780 is a `hidden beast` number, since 7 + 81 + 0 + 578 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 35569296 + 42536484 = 5964^2 + 6522^2 .

It is a super-2 number, since 2×78105780² = 12201025738816800, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 70914 + ... + 72006.

Almost surely, 2^78105780 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 78105780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118867476).

78105780 is an abundant number, since it is smaller than the sum of its proper divisors (159629172).

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

78105780 is a wasteful number, since it uses less digits than its factorization.

78105780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1505 (or 1500 counting only the distinct ones).

The product of its (nonzero) digits is 15680, while the sum is 36.

The square root of 78105780 is about 8837.7474505668. The cubic root of 78105780 is about 427.4589270071.

The spelling of 78105780 in words is "seventy-eight million, one hundred five thousand, seven hundred eighty".