21312191440 has 160 divisors (see below), whose sum is σ = 53248306176. Its totient is φ = 7904624640.

The previous prime is 21312191429. The next prime is 21312191441. The reversal of 21312191440 is 4419121312.

It is a junction number, because it is equal to n+sod(n) for n = 21312191399 and 21312191408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312191441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 49448025 + ... + 49448455.

Almost surely, 2^21312191440 is an apocalyptic number.

21312191440 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 21312191440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26624153088).

21312191440 is an abundant number, since it is smaller than the sum of its proper divisors (31936114736).

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

21312191440 is a wasteful number, since it uses less digits than its factorization.

21312191440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 917 (or 911 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The spelling of 21312191440 in words is "twenty-one billion, three hundred twelve million, one hundred ninety-one thousand, four hundred forty".