21731270649 has 16 divisors (see below), whose sum is σ = 31688760000. Its totient is φ = 13137284160.

The previous prime is 21731270633. The next prime is 21731270681. The reversal of 21731270649 is 94607213712.

It is not a de Polignac number, because 21731270649 - 2⁴ = 21731270633 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21731270649.

It is not an unprimeable number, because it can be changed into a prime (21731270699) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 816274 + ... + 842475.

It is an arithmetic number, because the mean of its divisors is an integer number (1980547500).

Almost surely, 2^21731270649 is an apocalyptic number.

It is an amenable number.

21731270649 is a deficient number, since it is larger than the sum of its proper divisors (9957489351).

21731270649 is a wasteful number, since it uses less digits than its factorization.

21731270649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1659160.

The product of its (nonzero) digits is 127008, while the sum is 42.

The spelling of 21731270649 in words is "twenty-one billion, seven hundred thirty-one million, two hundred seventy thousand, six hundred forty-nine".