1997937018251 has 2 divisors, whose sum is σ = 1997937018252. Its totient is φ = 1997937018250.

The previous prime is 1997937018239. The next prime is 1997937018281. The reversal of 1997937018251 is 1528107397991.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1528107397991) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1997937018251 is a prime.

It is not a weakly prime, because it can be changed into another prime (1997937018211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 998968509125 + 998968509126.

It is an arithmetic number, because the mean of its divisors is an integer number (998968509126).

Almost surely, 2^{1997937018251} is an apocalyptic number.

1997937018251 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997937018251 is an equidigital number, since it uses as much as digits as its factorization.

1997937018251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8573040, while the sum is 62.

The spelling of 1997937018251 in words is "one trillion, nine hundred ninety-seven billion, nine hundred thirty-seven million, eighteen thousand, two hundred fifty-one".