10101991997 has 2 divisors, whose sum is σ = 10101991998. Its totient is φ = 10101991996.

The previous prime is 10101991951. The next prime is 10101992003. The reversal of 10101991997 is 79919910101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9429575236 + 672416761 = 97106^2 + 25931^2 .

It is a cyclic number.

It is not a de Polignac number, because 10101991997 - 2²² = 10097797693 is a prime.

It is a super-3 number, since 3×10101991997³ (a number of 31 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10101991937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5050995998 + 5050995999.

It is an arithmetic number, because the mean of its divisors is an integer number (5050995999).

Almost surely, 2^10101991997 is an apocalyptic number.

It is an amenable number.

10101991997 is a deficient number, since it is larger than the sum of its proper divisors (1).

10101991997 is an equidigital number, since it uses as much as digits as its factorization.

10101991997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45927, while the sum is 47.

The spelling of 10101991997 in words is "ten billion, one hundred one million, nine hundred ninety-one thousand, nine hundred ninety-seven".