1251839091563 has 4 divisors (see below), whose sum is σ = 1317725359560. Its totient is φ = 1185952823568.

The previous prime is 1251839091493. The next prime is 1251839091617. The reversal of 1251839091563 is 3651909381521.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1251839091563 - 2¹² = 1251839087467 is a prime.

It is a super-2 number, since 2×1251839091563² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1251839091163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32943133970 + ... + 32943134007.

It is an arithmetic number, because the mean of its divisors is an integer number (329431339890).

Almost surely, 2^{1251839091563} is an apocalyptic number.

1251839091563 is a deficient number, since it is larger than the sum of its proper divisors (65886267997).

1251839091563 is an equidigital number, since it uses as much as digits as its factorization.

1251839091563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65886267996.

The product of its (nonzero) digits is 1749600, while the sum is 53.

The spelling of 1251839091563 in words is "one trillion, two hundred fifty-one billion, eight hundred thirty-nine million, ninety-one thousand, five hundred sixty-three".