81694131 has 16 divisors (see below), whose sum is σ = 115084800. Its totient is φ = 51463328.

The previous prime is 81694103. The next prime is 81694157. The reversal of 81694131 is 13149618.

It is a cyclic number.

It is not a de Polignac number, because 81694131 - 2⁷ = 81694003 is a prime.

It is a super-2 number, since 2×81694131² = 13347862079690322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81694092 and 81694101.

It is not an unprimeable number, because it can be changed into a prime (81694031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5901 + ... + 14078.

It is an arithmetic number, because the mean of its divisors is an integer number (7192800).

Almost surely, 2^81694131 is an apocalyptic number.

81694131 is a deficient number, since it is larger than the sum of its proper divisors (33390669).

81694131 is a wasteful number, since it uses less digits than its factorization.

81694131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20058.

The product of its digits is 5184, while the sum is 33.

The square root of 81694131 is about 9038.4805692107. The cubic root of 81694131 is about 433.9072957791.

The spelling of 81694131 in words is "eighty-one million, six hundred ninety-four thousand, one hundred thirty-one".