72611721 has 40 divisors (see below), whose sum is σ = 133514304. Its totient is φ = 38296800.

The previous prime is 72611681. The next prime is 72611729. The reversal of 72611721 is 12711627.

It is not a de Polignac number, because 72611721 - 2¹⁰ = 72610697 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (72611729) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2446 + ... + 12296.

Almost surely, 2^72611721 is an apocalyptic number.

It is an amenable number.

72611721 is a deficient number, since it is larger than the sum of its proper divisors (60902583).

72611721 is a wasteful number, since it uses less digits than its factorization.

72611721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9883 (or 9874 counting only the distinct ones).

The product of its digits is 1176, while the sum is 27.

The square root of 72611721 is about 8521.2511405309. The cubic root of 72611721 is about 417.1916204365.

The spelling of 72611721 in words is "seventy-two million, six hundred eleven thousand, seven hundred twenty-one".