81677257 has 4 divisors (see below), whose sum is σ = 85976080. Its totient is φ = 77378436.

The previous prime is 81677251. The next prime is 81677263. The reversal of 81677257 is 75277618.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (81677251) and next prime (81677263).

It is a cyclic number.

It is not a de Polignac number, because 81677257 - 2¹⁹ = 81152969 is a prime.

It is a super-2 number, since 2×81677257² = 13342348622088098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81677251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2149383 + ... + 2149420.

It is an arithmetic number, because the mean of its divisors is an integer number (21494020).

Almost surely, 2^81677257 is an apocalyptic number.

It is an amenable number.

81677257 is a deficient number, since it is larger than the sum of its proper divisors (4298823).

81677257 is a wasteful number, since it uses less digits than its factorization.

81677257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4298822.

The product of its digits is 164640, while the sum is 43.

The square root of 81677257 is about 9037.5470676506. The cubic root of 81677257 is about 433.8774190679.

The spelling of 81677257 in words is "eighty-one million, six hundred seventy-seven thousand, two hundred fifty-seven".