85991621 has 4 divisors (see below), whose sum is σ = 86272032. Its totient is φ = 85711212.

The previous prime is 85991617. The next prime is 85991657. The reversal of 85991621 is 12619958.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 85991621 - 2² = 85991617 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85991671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 139745 + ... + 140358.

It is an arithmetic number, because the mean of its divisors is an integer number (21568008).

Almost surely, 2^85991621 is an apocalyptic number.

It is an amenable number.

85991621 is a deficient number, since it is larger than the sum of its proper divisors (280411).

85991621 is a wasteful number, since it uses less digits than its factorization.

85991621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280410.

The product of its digits is 38880, while the sum is 41.

The square root of 85991621 is about 9273.1667190879. The cubic root of 85991621 is about 441.3861605276.

The spelling of 85991621 in words is "eighty-five million, nine hundred ninety-one thousand, six hundred twenty-one".