21398964240 has 80 divisors (see below), whose sum is σ = 66956839488. Its totient is φ = 5653052928.

The previous prime is 21398964211. The next prime is 21398964247. The reversal of 21398964240 is 4246989312.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21398964240.

It is not an unprimeable number, because it can be changed into a prime (21398964247) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 390967 + ... + 442326.

Almost surely, 2^21398964240 is an apocalyptic number.

21398964240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21398964240 is an abundant number, since it is smaller than the sum of its proper divisors (45557875248).

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

21398964240 is a wasteful number, since it uses less digits than its factorization.

21398964240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 833416 (or 833410 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 48.

The spelling of 21398964240 in words is "twenty-one billion, three hundred ninety-eight million, nine hundred sixty-four thousand, two hundred forty".