85785921 has 18 divisors (see below), whose sum is σ = 134180358. Its totient is φ = 52790400.

The previous prime is 85785911. The next prime is 85785923. The reversal of 85785921 is 12958758.

It is a happy number.

85785921 is a `hidden beast` number, since 8 + 57 + 8 + 592 + 1 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 408321 + 85377600 = 639^2 + 9240^2 .

It is not a de Polignac number, because 85785921 - 2⁷ = 85785793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (85785923) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 26680 + ... + 29721.

Almost surely, 2^85785921 is an apocalyptic number.

It is an amenable number.

85785921 is a deficient number, since it is larger than the sum of its proper divisors (48394437).

85785921 is a wasteful number, since it uses less digits than its factorization.

85785921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56433 (or 56417 counting only the distinct ones).

The product of its digits is 201600, while the sum is 45.

The square root of 85785921 is about 9262.0689373379. The cubic root of 85785921 is about 441.0339338659.

The spelling of 85785921 in words is "eighty-five million, seven hundred eighty-five thousand, nine hundred twenty-one".