72113981 has 4 divisors (see below), whose sum is σ = 74600700. Its totient is φ = 69627264.

The previous prime is 72113959. The next prime is 72114011. The reversal of 72113981 is 18931127.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36711481 + 35402500 = 6059^2 + 5950^2 .

It is a cyclic number.

It is not a de Polignac number, because 72113981 - 2⁶ = 72113917 is a prime.

It is a super-2 number, since 2×72113981² = 10400852511336722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72116981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1243316 + ... + 1243373.

It is an arithmetic number, because the mean of its divisors is an integer number (18650175).

Almost surely, 2^72113981 is an apocalyptic number.

It is an amenable number.

72113981 is a deficient number, since it is larger than the sum of its proper divisors (2486719).

72113981 is a wasteful number, since it uses less digits than its factorization.

72113981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2486718.

The product of its digits is 3024, while the sum is 32.

The square root of 72113981 is about 8491.9951130462. The cubic root of 72113981 is about 416.2361766790.

The spelling of 72113981 in words is "seventy-two million, one hundred thirteen thousand, nine hundred eighty-one".