21296390 has 16 divisors (see below), whose sum is σ = 40000608. Its totient is φ = 8148096.

The previous prime is 21296371. The next prime is 21296399. The reversal of 21296390 is 9369212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21296399) 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 7 ways as a sum of consecutive naturals, for example, 46067 + ... + 46526.

It is an arithmetic number, because the mean of its divisors is an integer number (2500038).

Almost surely, 2^21296390 is an apocalyptic number.

21296390 is a deficient number, since it is larger than the sum of its proper divisors (18704218).

21296390 is a wasteful number, since it uses less digits than its factorization.

21296390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92623.

The product of its (nonzero) digits is 5832, while the sum is 32.

The square root of 21296390 is about 4614.8011874836. The cubic root of 21296390 is about 277.1843230093.

The spelling of 21296390 in words is "twenty-one million, two hundred ninety-six thousand, three hundred ninety".