21075244666542 has 48 divisors (see below), whose sum is σ = 50072319496368. Its totient is φ = 6353347415040.

The previous prime is 21075244666513. The next prime is 21075244666573. The reversal of 21075244666542 is 24566644257012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 275714713 + ... + 275791140.

It is an arithmetic number, because the mean of its divisors is an integer number (1043173322841).

Almost surely, 2^{21075244666542} is an apocalyptic number.

21075244666542 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21075244666542 is an abundant number, since it is smaller than the sum of its proper divisors (28997074829826).

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

21075244666542 is a wasteful number, since it uses less digits than its factorization.

21075244666542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 551506065 (or 551506062 counting only the distinct ones).

The product of its (nonzero) digits is 19353600, while the sum is 54.

The spelling of 21075244666542 in words is "twenty-one trillion, seventy-five billion, two hundred forty-four million, six hundred sixty-six thousand, five hundred forty-two".