81423670 has 16 divisors (see below), whose sum is σ = 151291008. Its totient is φ = 31518720.

The previous prime is 81423653. The next prime is 81423679. The reversal of 81423670 is 7632418.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81423679) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131019 + ... + 131638.

It is an arithmetic number, because the mean of its divisors is an integer number (9455688).

Almost surely, 2^81423670 is an apocalyptic number.

81423670 is a deficient number, since it is larger than the sum of its proper divisors (69867338).

81423670 is a wasteful number, since it uses less digits than its factorization.

81423670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262695.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 81423670 is about 9023.5065246278. The cubic root of 81423670 is about 433.4279274097.

The spelling of 81423670 in words is "eighty-one million, four hundred twenty-three thousand, six hundred seventy".