21442464 has 36 divisors (see below), whose sum is σ = 60977826. Its totient is φ = 7147392.

The previous prime is 21442459. The next prime is 21442471. The reversal of 21442464 is 46424412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20250000 + 1192464 = 4500^2 + 1092^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

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, 36939 + ... + 37514.

Almost surely, 2^21442464 is an apocalyptic number.

21442464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21442464 is an abundant number, since it is smaller than the sum of its proper divisors (39535362).

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

21442464 is a wasteful number, since it uses less digits than its factorization.

21442464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74469 (or 74458 counting only the distinct ones).

The product of its digits is 6144, while the sum is 27.

The square root of 21442464 is about 4630.6008249470. The cubic root of 21442464 is about 277.8166242324.

Adding to 21442464 its reverse (46424412), we get a palindrome (67866876).

The spelling of 21442464 in words is "twenty-one million, four hundred forty-two thousand, four hundred sixty-four".