21045049820 has 48 divisors (see below), whose sum is σ = 44495474688. Its totient is φ = 8360904000.

The previous prime is 21045049787. The next prime is 21045049843. The reversal of 21045049820 is 2894054012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1836629 + ... + 1848051.

It is an arithmetic number, because the mean of its divisors is an integer number (926989056).

Almost surely, 2^21045049820 is an apocalyptic number.

21045049820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21045049820 is an abundant number, since it is smaller than the sum of its proper divisors (23450424868).

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

21045049820 is a wasteful number, since it uses less digits than its factorization.

21045049820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12050 (or 12048 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 35.

The spelling of 21045049820 in words is "twenty-one billion, forty-five million, forty-nine thousand, eight hundred twenty".