21453966 has 24 divisors (see below), whose sum is σ = 49218624. Its totient is φ = 6730560.

The previous prime is 21453961. The next prime is 21453967. The reversal of 21453966 is 66935412.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21453966.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21453961) 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 11 ways as a sum of consecutive naturals, for example, 34750 + ... + 35361.

It is an arithmetic number, because the mean of its divisors is an integer number (2050776).

Almost surely, 2^21453966 is an apocalyptic number.

21453966 is an abundant number, since it is smaller than the sum of its proper divisors (27764658).

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

21453966 is a wasteful number, since it uses less digits than its factorization.

21453966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70136 (or 70133 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 21453966 is about 4631.8426139065. The cubic root of 21453966 is about 277.8662900982.

The spelling of 21453966 in words is "twenty-one million, four hundred fifty-three thousand, nine hundred sixty-six".