21054042390 has 32 divisors (see below), whose sum is σ = 50544226656. Its totient is φ = 5612797440.

The previous prime is 21054042379. The next prime is 21054042419. The reversal of 21054042390 is 9324045012.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7134 + ... + 205326.

It is an arithmetic number, because the mean of its divisors is an integer number (1579507083).

Almost surely, 2^21054042390 is an apocalyptic number.

21054042390 is an abundant number, since it is smaller than the sum of its proper divisors (29490184266).

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

21054042390 is a wasteful number, since it uses less digits than its factorization.

21054042390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201744.

The product of its (nonzero) digits is 8640, while the sum is 30.

The spelling of 21054042390 in words is "twenty-one billion, fifty-four million, forty-two thousand, three hundred ninety".