1051204051991 has 2 divisors, whose sum is σ = 1051204051992. Its totient is φ = 1051204051990.

The previous prime is 1051204051957. The next prime is 1051204052009. The reversal of 1051204051991 is 1991504021501.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1051204051991 - 2¹⁸ = 1051203789847 is a prime.

It is a super-2 number, since 2×1051204051991² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1051204051921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 525602025995 + 525602025996.

It is an arithmetic number, because the mean of its divisors is an integer number (525602025996).

Almost surely, 2^{1051204051991} is an apocalyptic number.

1051204051991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1051204051991 is an equidigital number, since it uses as much as digits as its factorization.

1051204051991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16200, while the sum is 38.

The spelling of 1051204051991 in words is "one trillion, fifty-one billion, two hundred four million, fifty-one thousand, nine hundred ninety-one".