20992985 has 8 divisors (see below), whose sum is σ = 27129480. Its totient is φ = 15502464.

The previous prime is 20992981. The next prime is 20993003. The reversal of 20992985 is 58929902.

It can be written as a sum of positive squares in 4 ways, for example, as 80656 + 20912329 = 284^2 + 4573^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20992985 - 2² = 20992981 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20992981) 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, 161420 + ... + 161549.

It is an arithmetic number, because the mean of its divisors is an integer number (3391185).

Almost surely, 2^20992985 is an apocalyptic number.

It is an amenable number.

20992985 is a deficient number, since it is larger than the sum of its proper divisors (6136495).

20992985 is a wasteful number, since it uses less digits than its factorization.

20992985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322987.

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 20992985 is about 4581.8102317752. The cubic root of 20992985 is about 275.8616938150.

The spelling of 20992985 in words is "twenty million, nine hundred ninety-two thousand, nine hundred eighty-five".