21144036780 has 36 divisors (see below), whose sum is σ = 64136912112. Its totient is φ = 5638409760.

The previous prime is 21144036737. The next prime is 21144036811. The reversal of 21144036780 is 8763044112.

21144036780 is a `hidden beast` number, since 2 + 114 + 403 + 67 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58733256 + ... + 58733615.

It is an arithmetic number, because the mean of its divisors is an integer number (1781580892).

Almost surely, 2^21144036780 is an apocalyptic number.

21144036780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21144036780 is an abundant number, since it is smaller than the sum of its proper divisors (42992875332).

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

21144036780 is a wasteful number, since it uses less digits than its factorization.

21144036780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117466886 (or 117466881 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The spelling of 21144036780 in words is "twenty-one billion, one hundred forty-four million, thirty-six thousand, seven hundred eighty".