21393754890 has 64 divisors (see below), whose sum is σ = 54699048576. Its totient is φ = 5336451072.

The previous prime is 21393754871. The next prime is 21393754897. The reversal of 21393754890 is 9845739312.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (21393754897) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 45547 + ... + 211806.

It is an arithmetic number, because the mean of its divisors is an integer number (854672634).

Almost surely, 2^21393754890 is an apocalyptic number.

21393754890 is an abundant number, since it is smaller than the sum of its proper divisors (33305293686).

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

21393754890 is a wasteful number, since it uses less digits than its factorization.

21393754890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257543.

The product of its (nonzero) digits is 1632960, while the sum is 51.

The spelling of 21393754890 in words is "twenty-one billion, three hundred ninety-three million, seven hundred fifty-four thousand, eight hundred ninety".