72661 has 2 divisors, whose sum is σ = 72662. Its totient is φ = 72660.

The previous prime is 72649. The next prime is 72671. The reversal of 72661 is 16627.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44100 + 28561 = 210^2 + 169^2 .

It is a cyclic number.

It is not a de Polignac number, because 72661 - 2⁷ = 72533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36330 + 36331.

It is an arithmetic number, because the mean of its divisors is an integer number (36331).

2⁷²⁶⁶¹ is an apocalyptic number.

It is an amenable number.

72661 is a deficient number, since it is larger than the sum of its proper divisors (1).

72661 is an equidigital number, since it uses as much as digits as its factorization.

72661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 504, while the sum is 22.

The square root of 72661 is about 269.5570440556. The cubic root of 72661 is about 41.7285976814.

It can be divided in two parts, 726 and 61, that added together give a palindrome (787).

The spelling of 72661 in words is "seventy-two thousand, six hundred sixty-one".