21454992 has 120 divisors (see below), whose sum is σ = 65966264. Its totient is φ = 6469632.

The previous prime is 21454973. The next prime is 21454997. The reversal of 21454992 is 29945412.

21454992 is a `hidden beast` number, since 21 + 4 + 549 + 92 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 331776 + 21123216 = 576^2 + 4596^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21454997) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136578 + ... + 136734.

Almost surely, 2^21454992 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 21454992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32983132).

21454992 is an abundant number, since it is smaller than the sum of its proper divisors (44511272).

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

21454992 is a wasteful number, since it uses less digits than its factorization.

21454992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257 (or 248 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21454992 is about 4631.9533676409. The cubic root of 21454992 is about 277.8707195243.

The spelling of 21454992 in words is "twenty-one million, four hundred fifty-four thousand, nine hundred ninety-two".