21207744542 has 16 divisors (see below), whose sum is σ = 32652359712. Its totient is φ = 10324654080.

The previous prime is 21207744541. The next prime is 21207744553. The reversal of 21207744542 is 24544770212.

It is a junction number, because it is equal to n+sod(n) for n = 21207744496 and 21207744505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21207744541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 215843 + ... + 298334.

It is an arithmetic number, because the mean of its divisors is an integer number (2040772482).

Almost surely, 2^21207744542 is an apocalyptic number.

21207744542 is a deficient number, since it is larger than the sum of its proper divisors (11444615170).

21207744542 is a wasteful number, since it uses less digits than its factorization.

21207744542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 514723.

The product of its (nonzero) digits is 125440, while the sum is 38.

The spelling of 21207744542 in words is "twenty-one billion, two hundred seven million, seven hundred forty-four thousand, five hundred forty-two".