21166992 has 240 divisors, whose sum is σ = 77995008. Its totient is φ = 5195520.

The previous prime is 21166991. The next prime is 21166993. The reversal of 21166992 is 29966112.

It is an interprime number because it is at equal distance from previous prime (21166991) and next prime (21166993).

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

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21166991) 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, 254983 + ... + 255065.

Almost surely, 2^21166992 is an apocalyptic number.

21166992 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21166992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38997504).

21166992 is an abundant number, since it is smaller than the sum of its proper divisors (56828016).

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

21166992 is a wasteful number, since it uses less digits than its factorization.

21166992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138 (or 129 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 21166992 is about 4600.7599372278. The cubic root of 21166992 is about 276.6217865621.

The spelling of 21166992 in words is "twenty-one million, one hundred sixty-six thousand, nine hundred ninety-two".