21718481440 has 24 divisors (see below), whose sum is σ = 51309912780. Its totient is φ = 8687392512.

The previous prime is 21718481431. The next prime is 21718481441. The reversal of 21718481440 is 4418481712.

It can be written as a sum of positive squares in 2 ways, for example, as 21431788816 + 286692624 = 146396^2 + 16932^2 .

It is a super-3 number, since 3×21718481440³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 21718481393 and 21718481402.

It is not an unprimeable number, because it can be changed into a prime (21718481441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67870095 + ... + 67870414.

Almost surely, 2^21718481440 is an apocalyptic number.

21718481440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21718481440 is an abundant number, since it is smaller than the sum of its proper divisors (29591431340).

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

21718481440 is a wasteful number, since it uses less digits than its factorization.

21718481440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135740524 (or 135740516 counting only the distinct ones).

The product of its (nonzero) digits is 57344, while the sum is 40.

The spelling of 21718481440 in words is "twenty-one billion, seven hundred eighteen million, four hundred eighty-one thousand, four hundred forty".