21464440 has 32 divisors (see below), whose sum is σ = 49603680. Its totient is φ = 8353152.

The previous prime is 21464423. The next prime is 21464447. The reversal of 21464440 is 4446412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21464447) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5772 + ... + 8731.

It is an arithmetic number, because the mean of its divisors is an integer number (1550115).

Almost surely, 2^21464440 is an apocalyptic number.

21464440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21464440 is an abundant number, since it is smaller than the sum of its proper divisors (28139240).

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

21464440 is a wasteful number, since it uses less digits than its factorization.

21464440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14551 (or 14547 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 25.

The square root of 21464440 is about 4632.9731274852. The cubic root of 21464440 is about 277.9115015994.

It can be divided in two parts, 21464 and 440, that added together give a square (21904 = 148²).

The spelling of 21464440 in words is "twenty-one million, four hundred sixty-four thousand, four hundred forty".