20996181 has 12 divisors (see below), whose sum is σ = 30497740. Its totient is φ = 13919040.

The previous prime is 20996179. The next prime is 20996201. The reversal of 20996181 is 18169902.

It can be written as a sum of positive squares in 2 ways, for example, as 5267025 + 15729156 = 2295^2 + 3966^2 .

It is not a de Polignac number, because 20996181 - 2¹ = 20996179 is a prime.

It is a super-2 number, since 2×20996181² = 881679233169522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20996681) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4816 + ... + 8073.

Almost surely, 2^20996181 is an apocalyptic number.

It is an amenable number.

20996181 is a deficient number, since it is larger than the sum of its proper divisors (9501559).

20996181 is a wasteful number, since it uses less digits than its factorization.

20996181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13076 (or 13073 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 20996181 is about 4582.1589889483. The cubic root of 20996181 is about 275.8756922886.

The spelling of 20996181 in words is "twenty million, nine hundred ninety-six thousand, one hundred eighty-one".