81087042251 has 2 divisors, whose sum is σ = 81087042252. Its totient is φ = 81087042250.

The previous prime is 81087042241. The next prime is 81087042313. The reversal of 81087042251 is 15224078018.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81087042251 - 2²⁶ = 81019933387 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (81087042241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40543521125 + 40543521126.

It is an arithmetic number, because the mean of its divisors is an integer number (40543521126).

Almost surely, 2^81087042251 is an apocalyptic number.

81087042251 is a deficient number, since it is larger than the sum of its proper divisors (1).

81087042251 is an equidigital number, since it uses as much as digits as its factorization.

81087042251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 35840, while the sum is 38.

The spelling of 81087042251 in words is "eighty-one billion, eighty-seven million, forty-two thousand, two hundred fifty-one".