21136378020 has 48 divisors (see below), whose sum is σ = 60781374528. Its totient is φ = 5484032640.

The previous prime is 21136377979. The next prime is 21136378027. The reversal of 21136378020 is 2087363112.

It is not an unprimeable number, because it can be changed into a prime (21136378027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4758226 + ... + 4762665.

It is an arithmetic number, because the mean of its divisors is an integer number (1266278636).

Almost surely, 2^21136378020 is an apocalyptic number.

21136378020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21136378020 is an abundant number, since it is smaller than the sum of its proper divisors (39644996508).

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

21136378020 is a wasteful number, since it uses less digits than its factorization.

21136378020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9520940 (or 9520938 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The spelling of 21136378020 in words is "twenty-one billion, one hundred thirty-six million, three hundred seventy-eight thousand, twenty".