21476979840 has 128 divisors (see below), whose sum is σ = 72061041600. Its totient is φ = 5425754112.

The previous prime is 21476979817. The next prime is 21476979871. The reversal of 21476979840 is 4897967412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×21476979840² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

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, 257887 + ... + 330846.

Almost surely, 2^21476979840 is an apocalyptic number.

21476979840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21476979840 is an abundant number, since it is smaller than the sum of its proper divisors (50584061760).

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

21476979840 is a wasteful number, since it uses less digits than its factorization.

21476979840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588774 (or 588762 counting only the distinct ones).

The product of its (nonzero) digits is 6096384, while the sum is 57.

The spelling of 21476979840 in words is "twenty-one billion, four hundred seventy-six million, nine hundred seventy-nine thousand, eight hundred forty".