21170470464 has 504 divisors, whose sum is σ = 75963487392. Its totient is φ = 5568675840.

The previous prime is 21170470439. The next prime is 21170470483. The reversal of 21170470464 is 46407407112.

It is a happy number.

21170470464 is a `hidden beast` number, since 21 + 170 + 4 + 7 + 0 + 464 = 666.

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 71 ways as a sum of consecutive naturals, for example, 18202747 + ... + 18203909.

Almost surely, 2^21170470464 is an apocalyptic number.

21170470464 is a gapful number since it is divisible by the number (24) 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 21170470464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37981743696).

21170470464 is an abundant number, since it is smaller than the sum of its proper divisors (54793016928).

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

21170470464 is a wasteful number, since it uses less digits than its factorization.

21170470464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1235 (or 1209 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 36.

Adding to 21170470464 its reverse (46407407112), we get a palindrome (67577877576).

The spelling of 21170470464 in words is "twenty-one billion, one hundred seventy million, four hundred seventy thousand, four hundred sixty-four".