72638281 has 4 divisors (see below), whose sum is σ = 72858064. Its totient is φ = 72418500.

The previous prime is 72638231. The next prime is 72638287. The reversal of 72638281 is 18283627.

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: 18283627 = 97 ⋅188491.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72638281 is a prime.

It is a super-2 number, since 2×72638281² = 10552639733269922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 72638281.

It is not an unprimeable number, because it can be changed into a prime (72638287) by changing a digit.

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, 109395 + ... + 110056.

It is an arithmetic number, because the mean of its divisors is an integer number (18214516).

Almost surely, 2^72638281 is an apocalyptic number.

It is an amenable number.

72638281 is a deficient number, since it is larger than the sum of its proper divisors (219783).

72638281 is a wasteful number, since it uses less digits than its factorization.

72638281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219782.

The product of its digits is 32256, while the sum is 37.

The square root of 72638281 is about 8522.8094546341. The cubic root of 72638281 is about 417.2424811816.

The spelling of 72638281 in words is "seventy-two million, six hundred thirty-eight thousand, two hundred eighty-one".