20402227991 has 2 divisors, whose sum is σ = 20402227992. Its totient is φ = 20402227990.

The previous prime is 20402227961. The next prime is 20402227999. The reversal of 20402227991 is 19972220402.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20402227991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20402227999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10201113995 + 10201113996.

It is an arithmetic number, because the mean of its divisors is an integer number (10201113996).

Almost surely, 2^20402227991 is an apocalyptic number.

20402227991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20402227991 is an equidigital number, since it uses as much as digits as its factorization.

20402227991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 38.

The spelling of 20402227991 in words is "twenty billion, four hundred two million, two hundred twenty-seven thousand, nine hundred ninety-one".