21316090 has 8 divisors (see below), whose sum is σ = 38368980. Its totient is φ = 8526432.

The previous prime is 21316063. The next prime is 21316091. The reversal of 21316090 is 9061312.

It can be written as a sum of positive squares in 2 ways, for example, as 19210689 + 2105401 = 4383^2 + 1451^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21316091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1065795 + ... + 1065814.

Almost surely, 2^21316090 is an apocalyptic number.

21316090 is a deficient number, since it is larger than the sum of its proper divisors (17052890).

21316090 is a wasteful number, since it uses less digits than its factorization.

21316090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2131616.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 21316090 is about 4616.9351305818. The cubic root of 21316090 is about 277.2697654762.

It can be divided in two parts, 213160 and 90, that multiplied together give a square (19184400 = 4380²).

The spelling of 21316090 in words is "twenty-one million, three hundred sixteen thousand, ninety".