864842021 has 4 divisors (see below), whose sum is σ = 902443872. Its totient is φ = 827240172.

The previous prime is 864841979. The next prime is 864842063. The reversal of 864842021 is 120248468.

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 an interprime number because it is at equal distance from previous prime (864841979) and next prime (864842063).

It is not a de Polignac number, because 864842021 - 2²² = 860647717 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 (864842521) 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, 18800891 + ... + 18800936.

It is an arithmetic number, because the mean of its divisors is an integer number (225610968).

Almost surely, 2^864842021 is an apocalyptic number.

It is an amenable number.

864842021 is a deficient number, since it is larger than the sum of its proper divisors (37601851).

864842021 is a wasteful number, since it uses less digits than its factorization.

864842021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37601850.

The product of its (nonzero) digits is 24576, while the sum is 35.

The square root of 864842021 is about 29408.1964934948. The cubic root of 864842021 is about 952.7499346644.

The spelling of 864842021 in words is "eight hundred sixty-four million, eight hundred forty-two thousand, twenty-one".