21319090 has 16 divisors (see below), whose sum is σ = 41326488. Its totient is φ = 7871616.

The previous prime is 21319087. The next prime is 21319093. The reversal of 21319090 is 9091312.

It is an interprime number because it is at equal distance from previous prime (21319087) and next prime (21319093).

It can be written as a sum of positive squares in 4 ways, for example, as 7458361 + 13860729 = 2731^2 + 3723^2 .

It is not an unprimeable number, because it can be changed into a prime (21319093) 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, 81867 + ... + 82126.

Almost surely, 2^21319090 is an apocalyptic number.

21319090 is a deficient number, since it is larger than the sum of its proper divisors (20007398).

21319090 is a wasteful number, since it uses less digits than its factorization.

21319090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164013.

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 21319090 is about 4617.2600100059. The cubic root of 21319090 is about 277.2827724000.

The spelling of 21319090 in words is "twenty-one million, three hundred nineteen thousand, ninety".