81149973 has 8 divisors (see below), whose sum is σ = 108452736. Its totient is φ = 53973600.

The previous prime is 81149963. The next prime is 81149983. The reversal of 81149973 is 37994118.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81149963) and next prime (81149983).

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

It is not a de Polignac number, because 81149973 - 2¹⁷ = 81018901 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81149903) 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, 30088 + ... + 32673.

It is an arithmetic number, because the mean of its divisors is an integer number (13556592).

Almost surely, 2^81149973 is an apocalyptic number.

It is an amenable number.

81149973 is a deficient number, since it is larger than the sum of its proper divisors (27302763).

81149973 is a wasteful number, since it uses less digits than its factorization.

81149973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63195.

The product of its digits is 54432, while the sum is 42.

The square root of 81149973 is about 9008.3279802636. The cubic root of 81149973 is about 432.9417416335.

The spelling of 81149973 in words is "eighty-one million, one hundred forty-nine thousand, nine hundred seventy-three".