21517361964 has 180 divisors, whose sum is σ = 66828950496. Its totient is φ = 6016804416.

The previous prime is 21517361911. The next prime is 21517362001. The reversal of 21517361964 is 46916371512.

21517361964 is a `hidden beast` number, since 2 + 15 + 17 + 3 + 619 + 6 + 4 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 731754 + ... + 760590.

Almost surely, 2^21517361964 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21517361964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33414475248).

21517361964 is an abundant number, since it is smaller than the sum of its proper divisors (45311588532).

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

21517361964 is a wasteful number, since it uses less digits than its factorization.

21517361964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28914 (or 28896 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The spelling of 21517361964 in words is "twenty-one billion, five hundred seventeen million, three hundred sixty-one thousand, nine hundred sixty-four".