21190861440 has 768 divisors, whose sum is σ = 90419328000. Its totient is φ = 4671184896.

The previous prime is 21190861421. The next prime is 21190861501. The reversal of 21190861440 is 4416809112.

21190861440 is a `hidden beast` number, since 21 + 19 + 0 + 8 + 614 + 4 + 0 = 666.

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 = 21190861395 and 21190861404.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 24554449 + ... + 24555311.

It is an arithmetic number, because the mean of its divisors is an integer number (117733500).

Almost surely, 2^21190861440 is an apocalyptic number.

21190861440 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 21190861440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45209664000).

21190861440 is an abundant number, since it is smaller than the sum of its proper divisors (69228466560).

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

21190861440 is a wasteful number, since it uses less digits than its factorization.

21190861440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 934 (or 909 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The spelling of 21190861440 in words is "twenty-one billion, one hundred ninety million, eight hundred sixty-one thousand, four hundred forty".