21947464 has 96 divisors (see below), whose sum is σ = 53625600. Its totient is φ = 8236800.

The previous prime is 21947447. The next prime is 21947467. The reversal of 21947464 is 46474912.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21947467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 277777 + ... + 277855.

It is an arithmetic number, because the mean of its divisors is an integer number (558600).

Almost surely, 2^21947464 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 21947464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26812800).

21947464 is an abundant number, since it is smaller than the sum of its proper divisors (31678136).

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

21947464 is a wasteful number, since it uses less digits than its factorization.

21947464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 140 counting only the distinct ones).

The product of its digits is 48384, while the sum is 37.

The square root of 21947464 is about 4684.8120559954. The cubic root of 21947464 is about 279.9807129572.

The spelling of 21947464 in words is "twenty-one million, nine hundred forty-seven thousand, four hundred sixty-four".