21202029978 has 64 divisors (see below), whose sum is σ = 46493896320. Its totient is φ = 6415718400.

The previous prime is 21202029973. The next prime is 21202030037. The reversal of 21202029978 is 87992020212.

It is not an unprimeable number, because it can be changed into a prime (21202029973) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3460758 + ... + 3466878.

It is an arithmetic number, because the mean of its divisors is an integer number (726467130).

Almost surely, 2^21202029978 is an apocalyptic number.

21202029978 is an abundant number, since it is smaller than the sum of its proper divisors (25291866342).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21202029978 is a wasteful number, since it uses less digits than its factorization.

21202029978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7343.

The product of its (nonzero) digits is 72576, while the sum is 42.

The spelling of 21202029978 in words is "twenty-one billion, two hundred two million, twenty-nine thousand, nine hundred seventy-eight".