20391293381 has 2 divisors, whose sum is σ = 20391293382. Its totient is φ = 20391293380.

The previous prime is 20391293359. The next prime is 20391293401. The reversal of 20391293381 is 18339219302.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19555505281 + 835788100 = 139841^2 + 28910^2 .

It is a cyclic number.

It is not a de Polignac number, because 20391293381 - 2²² = 20387099077 is a prime.

It is a super-2 number, since 2×20391293381² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20391293281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10195646690 + 10195646691.

It is an arithmetic number, because the mean of its divisors is an integer number (10195646691).

Almost surely, 2^20391293381 is an apocalyptic number.

It is an amenable number.

20391293381 is a deficient number, since it is larger than the sum of its proper divisors (1).

20391293381 is an equidigital number, since it uses as much as digits as its factorization.

20391293381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69984, while the sum is 41.

The spelling of 20391293381 in words is "twenty billion, three hundred ninety-one million, two hundred ninety-three thousand, three hundred eighty-one".