85817421 has 8 divisors (see below), whose sum is σ = 127136960. Its totient is φ = 57211596.

The previous prime is 85817399. The next prime is 85817429. The reversal of 85817421 is 12471858.

85817421 is a `hidden beast` number, since 8 + 581 + 74 + 2 + 1 = 666.

It is not a de Polignac number, because 85817421 - 2⁹ = 85816909 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85817429) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1589185 + ... + 1589238.

It is an arithmetic number, because the mean of its divisors is an integer number (15892120).

Almost surely, 2^85817421 is an apocalyptic number.

It is an amenable number.

85817421 is a deficient number, since it is larger than the sum of its proper divisors (41319539).

85817421 is a wasteful number, since it uses less digits than its factorization.

85817421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3178432 (or 3178426 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

The square root of 85817421 is about 9263.7692652613. The cubic root of 85817421 is about 441.0879088021.

The spelling of 85817421 in words is "eighty-five million, eight hundred seventeen thousand, four hundred twenty-one".