81123970 has 8 divisors (see below), whose sum is σ = 146023164. Its totient is φ = 32449584.

The previous prime is 81123899. The next prime is 81124007. The reversal of 81123970 is 7932118.

It can be written as a sum of positive squares in 2 ways, for example, as 73222249 + 7901721 = 8557^2 + 2811^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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, 4056189 + ... + 4056208.

Almost surely, 2^81123970 is an apocalyptic number.

81123970 is a deficient number, since it is larger than the sum of its proper divisors (64899194).

81123970 is a wasteful number, since it uses less digits than its factorization.

81123970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8112404.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 81123970 is about 9006.8845890241. The cubic root of 81123970 is about 432.8954939829.

The spelling of 81123970 in words is "eighty-one million, one hundred twenty-three thousand, nine hundred seventy".