21197496665952 has 576 divisors, whose sum is σ = 65123134562304. Its totient is φ = 6523089408000.

The previous prime is 21197496665881. The next prime is 21197496665957. The reversal of 21197496665952 is 25956669479112.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21197496665957) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 19500916353 + ... + 19500917439.

It is an arithmetic number, because the mean of its divisors is an integer number (113060997504).

Almost surely, 2^{21197496665952} 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 21197496665952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32561567281152).

21197496665952 is an abundant number, since it is smaller than the sum of its proper divisors (43925637896352).

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

21197496665952 is a wasteful number, since it uses less digits than its factorization.

21197496665952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1731 (or 1720 counting only the distinct ones).

The product of its digits is 440899200, while the sum is 72.

The spelling of 21197496665952 in words is "twenty-one trillion, one hundred ninety-seven billion, four hundred ninety-six million, six hundred sixty-five thousand, nine hundred fifty-two".