72397451281 has 4 divisors (see below), whose sum is σ = 72461577700. Its totient is φ = 72333324864.

The previous prime is 72397451263. The next prime is 72397451299. The reversal of 72397451281 is 18215479327.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18215479327 = 1201 ⋅15166927.

It is an interprime number because it is at equal distance from previous prime (72397451263) and next prime (72397451299).

It can be written as a sum of positive squares in 2 ways, for example, as 40852494400 + 31544956881 = 202120^2 + 177609^2 .

It is a cyclic number.

It is not a de Polignac number, because 72397451281 - 2²⁵ = 72363896849 is a prime.

It is a super-2 number, since 2×72397451281² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72397451261) 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, 32061516 + ... + 32063773.

It is an arithmetic number, because the mean of its divisors is an integer number (18115394425).

Almost surely, 2^72397451281 is an apocalyptic number.

It is an amenable number.

72397451281 is a deficient number, since it is larger than the sum of its proper divisors (64126419).

72397451281 is a wasteful number, since it uses less digits than its factorization.

72397451281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64126418.

The product of its digits is 846720, while the sum is 49.

The spelling of 72397451281 in words is "seventy-two billion, three hundred ninety-seven million, four hundred fifty-one thousand, two hundred eighty-one".