81699377 has 4 divisors (see below), whose sum is σ = 81740400. Its totient is φ = 81658356.

The previous prime is 81699361. The next prime is 81699383. The reversal of 81699377 is 77399618.

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 a cyclic number.

It is not a de Polignac number, because 81699377 - 2⁴ = 81699361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81609377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17363 + ... + 21560.

It is an arithmetic number, because the mean of its divisors is an integer number (20435100).

Almost surely, 2^81699377 is an apocalyptic number.

It is an amenable number.

81699377 is a deficient number, since it is larger than the sum of its proper divisors (41023).

81699377 is a wasteful number, since it uses less digits than its factorization.

81699377 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41022.

The product of its digits is 571536, while the sum is 50.

The square root of 81699377 is about 9038.7707681963. The cubic root of 81699377 is about 433.9165833861.

The spelling of 81699377 in words is "eighty-one million, six hundred ninety-nine thousand, three hundred seventy-seven".