21192138 has 32 divisors (see below), whose sum is σ = 51376320. Its totient is φ = 6421680.

The previous prime is 21192137. The next prime is 21192161. The reversal of 21192138 is 83129112.

It is a super-2 number, since 2×21192138² = 898213426022088, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21192137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17245 + ... + 18432.

It is an arithmetic number, because the mean of its divisors is an integer number (1605510).

Almost surely, 2^21192138 is an apocalyptic number.

21192138 is an abundant number, since it is smaller than the sum of its proper divisors (30184182).

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

21192138 is a wasteful number, since it uses less digits than its factorization.

21192138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35699 (or 35693 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 21192138 is about 4603.4919354768. The cubic root of 21192138 is about 276.7312837572.

The spelling of 21192138 in words is "twenty-one million, one hundred ninety-two thousand, one hundred thirty-eight".