20622991 has 4 divisors (see below), whose sum is σ = 20854800. Its totient is φ = 20391184.

The previous prime is 20622983. The next prime is 20623003. The reversal of 20622991 is 19922602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20622991 - 2³ = 20622983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20622911) 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, 115771 + ... + 115948.

It is an arithmetic number, because the mean of its divisors is an integer number (5213700).

Almost surely, 2^20622991 is an apocalyptic number.

20622991 is a deficient number, since it is larger than the sum of its proper divisors (231809).

20622991 is an equidigital number, since it uses as much as digits as its factorization.

20622991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231808.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 20622991 is about 4541.2543421394. The cubic root of 20622991 is about 274.2314231092.

The spelling of 20622991 in words is "twenty million, six hundred twenty-two thousand, nine hundred ninety-one".