21156851484 has 96 divisors (see below), whose sum is σ = 57374714880. Its totient is φ = 6729307200.

The previous prime is 21156851453. The next prime is 21156851497. The reversal of 21156851484 is 48415865112.

21156851484 is a `hidden beast` number, since 2 + 1 + 1 + 56 + 8 + 514 + 84 = 666.

It is a super-2 number, since 2×21156851484² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1035649 + ... + 1055879.

It is an arithmetic number, because the mean of its divisors is an integer number (597653280).

Almost surely, 2^21156851484 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21156851484, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28687357440).

21156851484 is an abundant number, since it is smaller than the sum of its proper divisors (36217863396).

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

21156851484 is a wasteful number, since it uses less digits than its factorization.

21156851484 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20688 (or 20680 counting only the distinct ones).

The product of its digits is 307200, while the sum is 45.

The spelling of 21156851484 in words is "twenty-one billion, one hundred fifty-six million, eight hundred fifty-one thousand, four hundred eighty-four".