21231898 has 24 divisors (see below), whose sum is σ = 34139808. Its totient is φ = 9882312.

The previous prime is 21231893. The next prime is 21231923. The reversal of 21231898 is 89813212.

It is not an unprimeable number, because it can be changed into a prime (21231893) 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 11 ways as a sum of consecutive naturals, for example, 255765 + ... + 255847.

It is an arithmetic number, because the mean of its divisors is an integer number (1422492).

Almost surely, 2^21231898 is an apocalyptic number.

21231898 is a deficient number, since it is larger than the sum of its proper divisors (12907910).

21231898 is an equidigital number, since it uses as much as digits as its factorization.

21231898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258 (or 175 counting only the distinct ones).

The product of its digits is 6912, while the sum is 34.

The square root of 21231898 is about 4607.8083727516. The cubic root of 21231898 is about 276.9042403815.

The spelling of 21231898 in words is "twenty-one million, two hundred thirty-one thousand, eight hundred ninety-eight".