72347981 has 4 divisors (see below), whose sum is σ = 72420000. Its totient is φ = 72275964.

The previous prime is 72347969. The next prime is 72348043. The reversal of 72347981 is 18974327.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18974327 = 1489 ⋅12743.

It is a cyclic number.

It is not a de Polignac number, because 72347981 - 2¹⁰ = 72346957 is a prime.

It is a super-2 number, since 2×72347981² = 10468460709552722, 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 (72347381) 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, 34481 + ... + 36518.

It is an arithmetic number, because the mean of its divisors is an integer number (18105000).

Almost surely, 2^72347981 is an apocalyptic number.

It is an amenable number.

72347981 is a deficient number, since it is larger than the sum of its proper divisors (72019).

72347981 is a wasteful number, since it uses less digits than its factorization.

72347981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72018.

The product of its digits is 84672, while the sum is 41.

The square root of 72347981 is about 8505.7616355033. The cubic root of 72347981 is about 416.6859004099.

The spelling of 72347981 in words is "seventy-two million, three hundred forty-seven thousand, nine hundred eighty-one".