21641090 has 16 divisors (see below), whose sum is σ = 39159288. Its totient is φ = 8610816.

The previous prime is 21641027. The next prime is 21641093. The reversal of 21641090 is 9014612.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 8543929 + 13097161 = 2923^2 + 3619^2 .

It is not an unprimeable number, because it can be changed into a prime (21641093) 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, 3677 + ... + 7536.

Almost surely, 2^21641090 is an apocalyptic number.

21641090 is a deficient number, since it is larger than the sum of its proper divisors (17518198).

21641090 is a wasteful number, since it uses less digits than its factorization.

21641090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11413.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21641090 is about 4651.9984952706. The cubic root of 21641090 is about 278.6718134191.

The spelling of 21641090 in words is "twenty-one million, six hundred forty-one thousand, ninety".