81446251 has 2 divisors, whose sum is σ = 81446252. Its totient is φ = 81446250.

The previous prime is 81446177. The next prime is 81446279. The reversal of 81446251 is 15264418.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81446251 - 2¹³ = 81438059 is a prime.

It is equal to p_4749052 and since 81446251 and 4749052 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81446051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40723125 + 40723126.

It is an arithmetic number, because the mean of its divisors is an integer number (40723126).

Almost surely, 2^81446251 is an apocalyptic number.

81446251 is a deficient number, since it is larger than the sum of its proper divisors (1).

81446251 is an equidigital number, since it uses as much as digits as its factorization.

81446251 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7680, while the sum is 31.

The square root of 81446251 is about 9024.7576698768. The cubic root of 81446251 is about 433.4679908270.

The spelling of 81446251 in words is "eighty-one million, four hundred forty-six thousand, two hundred fifty-one".