21002210019978 has 32 divisors (see below), whose sum is σ = 47815308191232. Its totient is φ = 6087597106800.

The previous prime is 21002210019977. The next prime is 21002210020021. The reversal of 21002210019978 is 87991001220012.

It is not an unprimeable number, because it can be changed into a prime (21002210019977) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6917722468 + ... + 6917725503.

It is an arithmetic number, because the mean of its divisors is an integer number (1494228380976).

Almost surely, 2^{21002210019978} is an apocalyptic number.

21002210019978 is an abundant number, since it is smaller than the sum of its proper divisors (26813098171254).

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

21002210019978 is a wasteful number, since it uses less digits than its factorization.

21002210019978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13835448010.

The product of its (nonzero) digits is 36288, while the sum is 42.

The spelling of 21002210019978 in words is "twenty-one trillion, two billion, two hundred ten million, nineteen thousand, nine hundred seventy-eight".