78269521 has 16 divisors (see below), whose sum is σ = 89179200. Its totient is φ = 68040000.

The previous prime is 78269509. The next prime is 78269549. The reversal of 78269521 is 12596287.

It is a 5-Lehmer number, since φ(78269521) divides (78269521-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 78269521 - 2⁵ = 78269489 is a prime.

It is a super-2 number, since 2×78269521² = 12252235835138882, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78269501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33646 + ... + 35896.

It is an arithmetic number, because the mean of its divisors is an integer number (5573700).

Almost surely, 2^78269521 is an apocalyptic number.

It is an amenable number.

78269521 is a deficient number, since it is larger than the sum of its proper divisors (10909679).

78269521 is a wasteful number, since it uses less digits than its factorization.

78269521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2400.

The product of its digits is 60480, while the sum is 40.

The square root of 78269521 is about 8847.0063298271. The cubic root of 78269521 is about 427.7574268887.

The spelling of 78269521 in words is "seventy-eight million, two hundred sixty-nine thousand, five hundred twenty-one".