81722667 has 32 divisors (see below), whose sum is σ = 127814400. Its totient is φ = 45988992.

The previous prime is 81722651. The next prime is 81722777. The reversal of 81722667 is 76622718.

It is not a de Polignac number, because 81722667 - 2⁴ = 81722651 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (81722167) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19588 + ... + 23390.

It is an arithmetic number, because the mean of its divisors is an integer number (3994200).

Almost surely, 2^81722667 is an apocalyptic number.

81722667 is a gapful number since it is divisible by the number (87) formed by its first and last digit.

81722667 is a deficient number, since it is larger than the sum of its proper divisors (46091733).

81722667 is a wasteful number, since it uses less digits than its factorization.

81722667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3867.

The product of its digits is 56448, while the sum is 39.

The square root of 81722667 is about 9040.0590152941. The cubic root of 81722667 is about 433.9578115956.

The spelling of 81722667 in words is "eighty-one million, seven hundred twenty-two thousand, six hundred sixty-seven".