21487464 has 64 divisors (see below), whose sum is σ = 61632000. Its totient is φ = 6929280.

The previous prime is 21487441. The next prime is 21487469. The reversal of 21487464 is 46478412.

It is a super-2 number, since 2×21487464² = 923422218302592, which contains 22 as substring.

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 (21487469) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5092 + ... + 8300.

It is an arithmetic number, because the mean of its divisors is an integer number (963000).

Almost surely, 2^21487464 is an apocalyptic number.

21487464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21487464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30816000).

21487464 is an abundant number, since it is smaller than the sum of its proper divisors (40144536).

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

21487464 is a wasteful number, since it uses less digits than its factorization.

21487464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3255 (or 3245 counting only the distinct ones).

The product of its digits is 43008, while the sum is 36.

The square root of 21487464 is about 4635.4572589983. The cubic root of 21487464 is about 278.0108340756.

It can be divided in two parts, 214 and 87464, that added together give a palindrome (87678).

The spelling of 21487464 in words is "twenty-one million, four hundred eighty-seven thousand, four hundred sixty-four".