21355571730 has 32 divisors (see below), whose sum is σ = 51539716800. Its totient is φ = 5663003072.

The previous prime is 21355571693. The next prime is 21355571777. The reversal of 21355571730 is 3717555312.

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, 1983045 + ... + 1993784.

It is an arithmetic number, because the mean of its divisors is an integer number (1610616150).

Almost surely, 2^21355571730 is an apocalyptic number.

21355571730 is an abundant number, since it is smaller than the sum of its proper divisors (30184145070).

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

21355571730 is a wasteful number, since it uses less digits than its factorization.

21355571730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3977018.

The product of its (nonzero) digits is 110250, while the sum is 39.

The spelling of 21355571730 in words is "twenty-one billion, three hundred fifty-five million, five hundred seventy-one thousand, seven hundred thirty".