21157481428 has 24 divisors (see below), whose sum is σ = 37299592512. Its totient is φ = 10500733824.

The previous prime is 21157481417. The next prime is 21157481441. The reversal of 21157481428 is 82418475112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 271425 + ... + 340567.

It is an arithmetic number, because the mean of its divisors is an integer number (1554149688).

Almost surely, 2^21157481428 is an apocalyptic number.

It is an amenable number.

21157481428 is a deficient number, since it is larger than the sum of its proper divisors (16142111084).

21157481428 is a wasteful number, since it uses less digits than its factorization.

21157481428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69711 (or 69709 counting only the distinct ones).

The product of its digits is 143360, while the sum is 43.

The spelling of 21157481428 in words is "twenty-one billion, one hundred fifty-seven million, four hundred eighty-one thousand, four hundred twenty-eight".