21757747464 has 24 divisors (see below), whose sum is σ = 58927232910. Its totient is φ = 7252582464.

The previous prime is 21757747463. The next prime is 21757747469. The reversal of 21757747464 is 46474775712.

It is a happy number.

21757747464 is a `hidden beast` number, since 2 + 1 + 7 + 577 + 4 + 7 + 4 + 64 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21635468100 + 122279364 = 147090^2 + 11058^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21757747464.

It is not an unprimeable number, because it can be changed into a prime (21757747463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 151095397 + ... + 151095540.

Almost surely, 2^21757747464 is an apocalyptic number.

21757747464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21757747464 is an abundant number, since it is smaller than the sum of its proper divisors (37169485446).

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

21757747464 is a wasteful number, since it uses less digits than its factorization.

21757747464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302190949 (or 302190942 counting only the distinct ones).

The product of its digits is 9219840, while the sum is 54.

The spelling of 21757747464 in words is "twenty-one billion, seven hundred fifty-seven million, seven hundred forty-seven thousand, four hundred sixty-four".