21530457772 has 48 divisors (see below), whose sum is σ = 42621344640. Its totient is φ = 9455415552.

The previous prime is 21530457769. The next prime is 21530457787. The reversal of 21530457772 is 27775403512.

It is a super-2 number, since 2×21530457772² (a number of 21 digits) contains 22 as substring.

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, 37798 + ... + 210925.

It is an arithmetic number, because the mean of its divisors is an integer number (887944680).

Almost surely, 2^21530457772 is an apocalyptic number.

It is an amenable number.

21530457772 is a deficient number, since it is larger than the sum of its proper divisors (21090886868).

21530457772 is a wasteful number, since it uses less digits than its factorization.

21530457772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248830 (or 248828 counting only the distinct ones).

The product of its (nonzero) digits is 411600, while the sum is 43.

The spelling of 21530457772 in words is "twenty-one billion, five hundred thirty million, four hundred fifty-seven thousand, seven hundred seventy-two".