20723222591 has 2 divisors, whose sum is σ = 20723222592. Its totient is φ = 20723222590.

The previous prime is 20723222561. The next prime is 20723222629. The reversal of 20723222591 is 19522232702.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20723222591 is a prime.

It is a super-2 number, since 2×20723222591² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20723222561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10361611295 + 10361611296.

It is an arithmetic number, because the mean of its divisors is an integer number (10361611296).

Almost surely, 2^20723222591 is an apocalyptic number.

20723222591 is a deficient number, since it is larger than the sum of its proper divisors (1).

20723222591 is an equidigital number, since it uses as much as digits as its factorization.

20723222591 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 35.

The spelling of 20723222591 in words is "twenty billion, seven hundred twenty-three million, two hundred twenty-two thousand, five hundred ninety-one".