21730607720 has 32 divisors (see below), whose sum is σ = 48907798920. Its totient is φ = 8689766400.

The previous prime is 21730607707. The next prime is 21730607737. The reversal of 21730607720 is 2770603712.

It can be written as a sum of positive squares in 4 ways, for example, as 11630759716 + 10099848004 = 107846^2 + 100498^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68120 + ... + 219320.

Almost surely, 2^21730607720 is an apocalyptic number.

21730607720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21730607720 is an abundant number, since it is smaller than the sum of its proper divisors (27177191200).

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

21730607720 is a wasteful number, since it uses less digits than its factorization.

21730607720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154805 (or 154801 counting only the distinct ones).

The product of its (nonzero) digits is 24696, while the sum is 35.

The spelling of 21730607720 in words is "twenty-one billion, seven hundred thirty million, six hundred seven thousand, seven hundred twenty".