21900109392 has 90 divisors (see below), whose sum is σ = 71296425018. Its totient is φ = 6257172096.

The previous prime is 21900109313. The next prime is 21900109397. The reversal of 21900109392 is 29390100912.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20367856656 + 1532252736 = 142716^2 + 39144^2 .

It is a super-2 number, since 2×21900109392² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21900109397) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1544823 + ... + 1558934.

Almost surely, 2^21900109392 is an apocalyptic number.

It is an amenable number.

21900109392 is an abundant number, since it is smaller than the sum of its proper divisors (49396315626).

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

21900109392 is a wasteful number, since it uses less digits than its factorization.

21900109392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3103785 (or 3103769 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The spelling of 21900109392 in words is "twenty-one billion, nine hundred million, one hundred nine thousand, three hundred ninety-two".