21231490 has 16 divisors (see below), whose sum is σ = 43676352. Its totient is φ = 7279344.

The previous prime is 21231473. The next prime is 21231499. The reversal of 21231490 is 9413212.

It is not an unprimeable number, because it can be changed into a prime (21231499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151584 + ... + 151723.

It is an arithmetic number, because the mean of its divisors is an integer number (2729772).

Almost surely, 2^21231490 is an apocalyptic number.

21231490 is an abundant number, since it is smaller than the sum of its proper divisors (22444862).

21231490 is a wasteful number, since it uses less digits than its factorization.

21231490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303321.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21231490 is about 4607.7640998645. The cubic root of 21231490 is about 276.9024666720.

The spelling of 21231490 in words is "twenty-one million, two hundred thirty-one thousand, four hundred ninety".