21154357440 has 224 divisors, whose sum is σ = 74732448960. Its totient is φ = 5633261568.

The previous prime is 21154357409. The next prime is 21154357453. The reversal of 21154357440 is 4475345112.

21154357440 is a `hidden beast` number, since 2 + 1 + 1 + 5 + 43 + 574 + 40 = 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 = 21154357395 and 21154357404.

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, 8751112 + ... + 8753528.

Almost surely, 2^21154357440 is an apocalyptic number.

21154357440 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 21154357440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37366224480).

21154357440 is an abundant number, since it is smaller than the sum of its proper divisors (53578091520).

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

21154357440 is a wasteful number, since it uses less digits than its factorization.

21154357440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3456 (or 3440 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 36.

The spelling of 21154357440 in words is "twenty-one billion, one hundred fifty-four million, three hundred fifty-seven thousand, four hundred forty".