21200647440 has 160 divisors (see below), whose sum is σ = 78376697856. Its totient is φ = 4635164160.

The previous prime is 21200647439. The next prime is 21200647451. The reversal of 21200647440 is 4474600212.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21200647398 and 21200647407.

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, 235696 + ... + 312975.

Almost surely, 2^21200647440 is an apocalyptic number.

21200647440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200647440 is an abundant number, since it is smaller than the sum of its proper divisors (57176050416).

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

21200647440 is a wasteful number, since it uses less digits than its factorization.

21200647440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548717 (or 548711 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 30.

The spelling of 21200647440 in words is "twenty-one billion, two hundred million, six hundred forty-seven thousand, four hundred forty".