21157740265 has 16 divisors (see below), whose sum is σ = 25441827840. Its totient is φ = 16891208320.

The previous prime is 21157740223. The next prime is 21157740271. The reversal of 21157740265 is 56204775112.

It is not a de Polignac number, because 21157740265 - 2¹³ = 21157732073 is a prime.

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, 9044466 + ... + 9046804.

It is an arithmetic number, because the mean of its divisors is an integer number (1590114240).

Almost surely, 2^21157740265 is an apocalyptic number.

It is an amenable number.

21157740265 is a deficient number, since it is larger than the sum of its proper divisors (4284087575).

21157740265 is a wasteful number, since it uses less digits than its factorization.

21157740265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5312.

The product of its (nonzero) digits is 117600, while the sum is 40.

The spelling of 21157740265 in words is "twenty-one billion, one hundred fifty-seven million, seven hundred forty thousand, two hundred sixty-five".