21166851024 has 120 divisors (see below), whose sum is σ = 65250948672. Its totient is φ = 6351874560.

The previous prime is 21166850993. The next prime is 21166851049. The reversal of 21166851024 is 42015866112.

It is a happy number.

21166851024 is a `hidden beast` number, since 2 + 116 + 6 + 8 + 510 + 24 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21166851024.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 98284 + ... + 228020.

Almost surely, 2^21166851024 is an apocalyptic number.

21166851024 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21166851024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32625474336).

21166851024 is an abundant number, since it is smaller than the sum of its proper divisors (44084097648).

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

21166851024 is a wasteful number, since it uses less digits than its factorization.

21166851024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129865 (or 129856 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The spelling of 21166851024 in words is "twenty-one billion, one hundred sixty-six million, eight hundred fifty-one thousand, twenty-four".