21316155840 has 1008 divisors, whose sum is σ = 93396303936. Its totient is φ = 4352901120.

The previous prime is 21316155827. The next prime is 21316155859. The reversal of 21316155840 is 4855161312.

21316155840 is a `hidden beast` number, since 2 + 1 + 3 + 1 + 61 + 558 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (1008).

It is a super-2 number, since 2×21316155840² (a number of 21 digits) contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 21316155795 and 21316155804.

It is a congruent number.

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 143 ways as a sum of consecutive naturals, for example, 519906220 + ... + 519906260.

Almost surely, 2^21316155840 is an apocalyptic number.

21316155840 is a gapful number since it is divisible by the number (20) 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 21316155840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46698151968).

21316155840 is an abundant number, since it is smaller than the sum of its proper divisors (72080148096).

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

21316155840 is a wasteful number, since it uses less digits than its factorization.

21316155840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166 (or 112 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The spelling of 21316155840 in words is "twenty-one billion, three hundred sixteen million, one hundred fifty-five thousand, eight hundred forty".