78527781 has 12 divisors (see below), whose sum is σ = 113506380. Its totient is φ = 52316160.

The previous prime is 78527759. The next prime is 78527807. The reversal of 78527781 is 18772587.

It can be written as a sum of positive squares in 2 ways, for example, as 48650625 + 29877156 = 6975^2 + 5466^2 .

It is not a de Polignac number, because 78527781 - 2⁶ = 78527717 is a prime.

It is a super-2 number, since 2×78527781² = 12333224777567922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78527731) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21925 + ... + 25253.

It is an arithmetic number, because the mean of its divisors is an integer number (9458865).

Almost surely, 2^78527781 is an apocalyptic number.

It is an amenable number.

78527781 is a deficient number, since it is larger than the sum of its proper divisors (34978599).

78527781 is a wasteful number, since it uses less digits than its factorization.

78527781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5956 (or 5953 counting only the distinct ones).

The product of its digits is 219520, while the sum is 45.

The square root of 78527781 is about 8861.5902071807. The cubic root of 78527781 is about 428.2273899422.

The spelling of 78527781 in words is "seventy-eight million, five hundred twenty-seven thousand, seven hundred eighty-one".