21432490 has 16 divisors (see below), whose sum is σ = 39476448. Its totient is φ = 8373456.

The previous prime is 21432473. The next prime is 21432493. The reversal of 21432490 is 9423412.

It is not an unprimeable number, because it can be changed into a prime (21432493) 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, 24492 + ... + 25351.

It is an arithmetic number, because the mean of its divisors is an integer number (2467278).

Almost surely, 2^21432490 is an apocalyptic number.

21432490 is a deficient number, since it is larger than the sum of its proper divisors (18043958).

21432490 is a wasteful number, since it uses less digits than its factorization.

21432490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49893.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 21432490 is about 4629.5237336037. The cubic root of 21432490 is about 277.7735419206.

The spelling of 21432490 in words is "twenty-one million, four hundred thirty-two thousand, four hundred ninety".