20916081 has 24 divisors (see below), whose sum is σ = 31135104. Its totient is φ = 13524000.

The previous prime is 20916073. The next prime is 20916089. The reversal of 20916081 is 18061902.

It is an interprime number because it is at equal distance from previous prime (20916073) and next prime (20916089).

It is not a de Polignac number, because 20916081 - 2³ = 20916073 is a prime.

It is a super-2 number, since 2×20916081² = 874964888797122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20916089) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 83206 + ... + 83456.

It is an arithmetic number, because the mean of its divisors is an integer number (1297296).

Almost surely, 2^20916081 is an apocalyptic number.

It is an amenable number.

20916081 is a deficient number, since it is larger than the sum of its proper divisors (10219023).

20916081 is a wasteful number, since it uses less digits than its factorization.

20916081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 501 (or 498 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 20916081 is about 4573.4102155831. The cubic root of 20916081 is about 275.5244251804.

Adding to 20916081 its reverse (18061902), we get a palindrome (38977983).

It can be divided in two parts, 209 and 16081, that added together give a triangular number (16290 = T₁₈₀).

The spelling of 20916081 in words is "twenty million, nine hundred sixteen thousand, eighty-one".