21456620460 has 144 divisors (see below), whose sum is σ = 71057226240. Its totient is φ = 5197553280.

The previous prime is 21456620453. The next prime is 21456620509. The reversal of 21456620460 is 6402665412.

21456620460 is a `hidden beast` number, since 2 + 14 + 566 + 20 + 4 + 60 = 666.

It is a super-2 number, since 2×21456620460² (a number of 21 digits) contains 22 as substring.

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 47 ways as a sum of consecutive naturals, for example, 3122989 + ... + 3129851.

It is an arithmetic number, because the mean of its divisors is an integer number (493452960).

Almost surely, 2^21456620460 is an apocalyptic number.

21456620460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21456620460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35528613120).

21456620460 is an abundant number, since it is smaller than the sum of its proper divisors (49600605780).

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

21456620460 is a wasteful number, since it uses less digits than its factorization.

21456620460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8468 (or 8463 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The spelling of 21456620460 in words is "twenty-one billion, four hundred fifty-six million, six hundred twenty thousand, four hundred sixty".