81395667 has 6 divisors (see below), whose sum is σ = 117571532. Its totient is φ = 54263772.

The previous prime is 81395653. The next prime is 81395683. The reversal of 81395667 is 76659318.

It is a happy number.

81395667 is a `hidden beast` number, since 81 + 3 + 9 + 566 + 7 = 666.

It is not a de Polignac number, because 81395667 - 2¹⁴ = 81379283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81395767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4521973 + ... + 4521990.

Almost surely, 2^81395667 is an apocalyptic number.

81395667 is a deficient number, since it is larger than the sum of its proper divisors (36175865).

81395667 is a wasteful number, since it uses less digits than its factorization.

81395667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9043969 (or 9043966 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 81395667 is about 9021.9547216776. The cubic root of 81395667 is about 433.3782339404.

The spelling of 81395667 in words is "eighty-one million, three hundred ninety-five thousand, six hundred sixty-seven".