21167397492 has 12 divisors (see below), whose sum is σ = 49390594176. Its totient is φ = 7055799160.

The previous prime is 21167397481. The next prime is 21167397499. The reversal of 21167397492 is 29479376112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21167397499) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 881974884 + ... + 881974907.

It is an arithmetic number, because the mean of its divisors is an integer number (4115882848).

Almost surely, 2^21167397492 is an apocalyptic number.

It is an amenable number.

21167397492 is an abundant number, since it is smaller than the sum of its proper divisors (28223196684).

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

21167397492 is a wasteful number, since it uses less digits than its factorization.

21167397492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1763949798 (or 1763949796 counting only the distinct ones).

The product of its digits is 1143072, while the sum is 51.

The spelling of 21167397492 in words is "twenty-one billion, one hundred sixty-seven million, three hundred ninety-seven thousand, four hundred ninety-two".