21390179760 has 80 divisors (see below), whose sum is σ = 73677293280. Its totient is φ = 5704047360.

The previous prime is 21390179693. The next prime is 21390179761. The reversal of 21390179760 is 6797109312.

21390179760 is a `hidden beast` number, since 21 + 390 + 179 + 76 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×21390179760² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21390179761) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4949271 + ... + 4953590.

It is an arithmetic number, because the mean of its divisors is an integer number (920966166).

Almost surely, 2^21390179760 is an apocalyptic number.

21390179760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21390179760 is an abundant number, since it is smaller than the sum of its proper divisors (52287113520).

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

21390179760 is a wasteful number, since it uses less digits than its factorization.

21390179760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9902883 (or 9902871 counting only the distinct ones).

The product of its (nonzero) digits is 142884, while the sum is 45.

The spelling of 21390179760 in words is "twenty-one billion, three hundred ninety million, one hundred seventy-nine thousand, seven hundred sixty".