81436671 has 10 divisors (see below), whose sum is σ = 121652432. Its totient is φ = 54291060.

The previous prime is 81436661. The next prime is 81436723. The reversal of 81436671 is 17663418.

It is not a de Polignac number, because 81436671 - 2⁵ = 81436639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81436631) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 502615 + ... + 502776.

Almost surely, 2^81436671 is an apocalyptic number.

81436671 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81436671 is a deficient number, since it is larger than the sum of its proper divisors (40215761).

81436671 is a wasteful number, since it uses less digits than its factorization.

81436671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1005403 (or 1005394 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 81436671 is about 9024.2268920944. The cubic root of 81436671 is about 433.4509948076.

The spelling of 81436671 in words is "eighty-one million, four hundred thirty-six thousand, six hundred seventy-one".