21453948 has 18 divisors (see below), whose sum is σ = 54230904. Its totient is φ = 7151304.

The previous prime is 21453937. The next prime is 21453961. The reversal of 21453948 is 84935412.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 595943 = 21453948 / (2 + 1 + 4 + 5 + 3 + 9 + 4 + 8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 297936 + ... + 298007.

It is an arithmetic number, because the mean of its divisors is an integer number (3012828).

Almost surely, 2^21453948 is an apocalyptic number.

It is an amenable number.

21453948 is an abundant number, since it is smaller than the sum of its proper divisors (32776956).

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

21453948 is a wasteful number, since it uses less digits than its factorization.

21453948 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 595953 (or 595948 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 21453948 is about 4631.8406708349. The cubic root of 21453948 is about 277.8662123877.

The spelling of 21453948 in words is "twenty-one million, four hundred fifty-three thousand, nine hundred forty-eight".