20072991 has 4 divisors (see below), whose sum is σ = 26763992. Its totient is φ = 13381992.

The previous prime is 20072989. The next prime is 20072993. The reversal of 20072991 is 19927002.

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

It is an interprime number because it is at equal distance from previous prime (20072989) and next prime (20072993).

It is not a de Polignac number, because 20072991 - 2¹ = 20072989 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 (20072993) 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, 3345496 + ... + 3345501.

It is an arithmetic number, because the mean of its divisors is an integer number (6690998).

Almost surely, 2^20072991 is an apocalyptic number.

20072991 is a deficient number, since it is larger than the sum of its proper divisors (6691001).

20072991 is an equidigital number, since it uses as much as digits as its factorization.

20072991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6691000.

The product of its (nonzero) digits is 2268, while the sum is 30.

The square root of 20072991 is about 4480.2891647750. The cubic root of 20072991 is about 271.7715741889.

Adding to 20072991 its reverse (19927002), we get a palindrome (39999993).

The spelling of 20072991 in words is "twenty million, seventy-two thousand, nine hundred ninety-one".