81256051 has 2 divisors, whose sum is σ = 81256052. Its totient is φ = 81256050.

The previous prime is 81256009. The next prime is 81256067. The reversal of 81256051 is 15065218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81256051 - 2⁹ = 81255539 is a prime.

It is a super-2 number, since 2×81256051² = 13205091648229202, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81256151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40628025 + 40628026.

It is an arithmetic number, because the mean of its divisors is an integer number (40628026).

Almost surely, 2^81256051 is an apocalyptic number.

81256051 is a deficient number, since it is larger than the sum of its proper divisors (1).

81256051 is an equidigital number, since it uses as much as digits as its factorization.

81256051 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 81256051 is about 9014.2138314997. The cubic root of 81256051 is about 433.1303044299.

The spelling of 81256051 in words is "eighty-one million, two hundred fifty-six thousand, fifty-one".