71868721 has 4 divisors (see below), whose sum is σ = 74993472. Its totient is φ = 68743972.

The previous prime is 71868701. The next prime is 71868739. The reversal of 71868721 is 12786817.

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.

It is a cyclic number.

It is not a de Polignac number, because 71868721 - 2²³ = 63480113 is a prime.

It is a super-2 number, since 2×71868721² = 10330226116351682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71868701) 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, 1562341 + ... + 1562386.

It is an arithmetic number, because the mean of its divisors is an integer number (18748368).

Almost surely, 2^71868721 is an apocalyptic number.

It is an amenable number.

71868721 is a deficient number, since it is larger than the sum of its proper divisors (3124751).

71868721 is a wasteful number, since it uses less digits than its factorization.

71868721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3124750.

The product of its digits is 37632, while the sum is 40.

The square root of 71868721 is about 8477.5421556015. The cubic root of 71868721 is about 415.7637669641.

The spelling of 71868721 in words is "seventy-one million, eight hundred sixty-eight thousand, seven hundred twenty-one".