21170124664 has 128 divisors (see below), whose sum is σ = 44840880000. Its totient is φ = 9306316800.

The previous prime is 21170124631. The next prime is 21170124697. The reversal of 21170124664 is 46642107112.

It is an interprime number because it is at equal distance from previous prime (21170124631) and next prime (21170124697).

It is a super-2 number, since 2×21170124664² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51760492 + ... + 51760900.

It is an arithmetic number, because the mean of its divisors is an integer number (350319375).

Almost surely, 2^21170124664 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 21170124664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22420440000).

21170124664 is an abundant number, since it is smaller than the sum of its proper divisors (23670755336).

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

21170124664 is a wasteful number, since it uses less digits than its factorization.

21170124664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 729 (or 725 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

The spelling of 21170124664 in words is "twenty-one billion, one hundred seventy million, one hundred twenty-four thousand, six hundred sixty-four".