21207715242 has 32 divisors (see below), whose sum is σ = 48515524992. Its totient is φ = 6054253824.

The previous prime is 21207715223. The next prime is 21207715247. The reversal of 21207715242 is 24251770212.

It is not an unprimeable number, because it can be changed into a prime (21207715247) 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, 161523 + ... + 261734.

It is an arithmetic number, because the mean of its divisors is an integer number (1516110156).

Almost surely, 2^21207715242 is an apocalyptic number.

21207715242 is an abundant number, since it is smaller than the sum of its proper divisors (27307809750).

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

21207715242 is a wasteful number, since it uses less digits than its factorization.

21207715242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424462.

The product of its (nonzero) digits is 15680, while the sum is 33.

The spelling of 21207715242 in words is "twenty-one billion, two hundred seven million, seven hundred fifteen thousand, two hundred forty-two".