20781213400 has 24 divisors (see below), whose sum is σ = 48316321620. Its totient is φ = 8312485280.

The previous prime is 20781213379. The next prime is 20781213473. The reversal of 20781213400 is 431218702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 51952834 + ... + 51953233.

Almost surely, 2^20781213400 is an apocalyptic number.

20781213400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20781213400 is an abundant number, since it is smaller than the sum of its proper divisors (27535108220).

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

20781213400 is a wasteful number, since it uses less digits than its factorization.

20781213400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103906083 (or 103906074 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The spelling of 20781213400 in words is "twenty billion, seven hundred eighty-one million, two hundred thirteen thousand, four hundred".