978658870021 has 4 divisors (see below), whose sum is σ = 1118467280032. Its totient is φ = 838850460012.

The previous prime is 978658869931. The next prime is 978658870061. The reversal of 978658870021 is 120078856879.

978658870021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 978658870021 - 2²⁵ = 978625315589 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 (978658870061) 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, 69904204995 + ... + 69904205008.

It is an arithmetic number, because the mean of its divisors is an integer number (279616820008).

Almost surely, 2^978658870021 is an apocalyptic number.

It is an amenable number.

978658870021 is a deficient number, since it is larger than the sum of its proper divisors (139808410011).

978658870021 is a wasteful number, since it uses less digits than its factorization.

978658870021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139808410010.

The product of its (nonzero) digits is 13547520, while the sum is 61.

The spelling of 978658870021 in words is "nine hundred seventy-eight billion, six hundred fifty-eight million, eight hundred seventy thousand, twenty-one".