21657725570 has 32 divisors (see below), whose sum is σ = 42367857840. Its totient is φ = 7923329280.

The previous prime is 21657725561. The next prime is 21657725597. The reversal of 21657725570 is 7552775612.

It can be written as a sum of positive squares in 8 ways, for example, as 3934927441 + 17722798129 = 62729^2 + 133127^2 .

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, 750041 + ... + 778380.

Almost surely, 2^21657725570 is an apocalyptic number.

21657725570 is a deficient number, since it is larger than the sum of its proper divisors (20710132270).

21657725570 is a wasteful number, since it uses less digits than its factorization.

21657725570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1528550.

The product of its (nonzero) digits is 1029000, while the sum is 47.

The spelling of 21657725570 in words is "twenty-one billion, six hundred fifty-seven million, seven hundred twenty-five thousand, five hundred seventy".