21948664764 has 144 divisors (see below), whose sum is σ = 57716736000. Its totient is φ = 6481762560.

The previous prime is 21948664763. The next prime is 21948664807. The reversal of 21948664764 is 46746684912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21948664763) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7982862 + ... + 7985610.

Almost surely, 2^21948664764 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 21948664764, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28858368000).

21948664764 is an abundant number, since it is smaller than the sum of its proper divisors (35768071236).

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

21948664764 is a wasteful number, since it uses less digits than its factorization.

21948664764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2940 (or 2925 counting only the distinct ones).

The product of its digits is 13934592, while the sum is 57.

The spelling of 21948664764 in words is "twenty-one billion, nine hundred forty-eight million, six hundred sixty-four thousand, seven hundred sixty-four".