21921207450 has 24 divisors (see below), whose sum is σ = 54364594848. Its totient is φ = 5845655280.

The previous prime is 21921207433. The next prime is 21921207461. The reversal of 21921207450 is 5470212912.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 73070542 + ... + 73070841.

It is an arithmetic number, because the mean of its divisors is an integer number (2265191452).

Almost surely, 2^21921207450 is an apocalyptic number.

21921207450 is an abundant number, since it is smaller than the sum of its proper divisors (32443387398).

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

21921207450 is a wasteful number, since it uses less digits than its factorization.

21921207450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146141398 (or 146141393 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 33.

The spelling of 21921207450 in words is "twenty-one billion, nine hundred twenty-one million, two hundred seven thousand, four hundred fifty".