21157367730 has 64 divisors (see below), whose sum is σ = 53562470400. Its totient is φ = 5333791680.

The previous prime is 21157367677. The next prime is 21157367761. The reversal of 21157367730 is 3776375112.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 234285 + ... + 311775.

It is an arithmetic number, because the mean of its divisors is an integer number (836913600).

Almost surely, 2^21157367730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21157367730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26781235200).

21157367730 is an abundant number, since it is smaller than the sum of its proper divisors (32405102670).

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

21157367730 is a wasteful number, since it uses less digits than its factorization.

21157367730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77999.

The product of its (nonzero) digits is 185220, while the sum is 42.

The spelling of 21157367730 in words is "twenty-one billion, one hundred fifty-seven million, three hundred sixty-seven thousand, seven hundred thirty".