72637661 has 2 divisors, whose sum is σ = 72637662. Its totient is φ = 72637660.

The previous prime is 72637633. The next prime is 72637667. The reversal of 72637661 is 16673627.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54096025 + 18541636 = 7355^2 + 4306^2 .

It is an emirp because it is prime and its reverse (16673627) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72637661 - 2¹⁰ = 72636637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72637667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36318830 + 36318831.

It is an arithmetic number, because the mean of its divisors is an integer number (36318831).

Almost surely, 2^72637661 is an apocalyptic number.

72637661 is the 3812-nd centered decagonal number.

It is an amenable number.

72637661 is a deficient number, since it is larger than the sum of its proper divisors (1).

72637661 is an equidigital number, since it uses as much as digits as its factorization.

72637661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 63504, while the sum is 38.

The square root of 72637661 is about 8522.7730815739. The cubic root of 72637661 is about 417.2412940615.

The spelling of 72637661 in words is "seventy-two million, six hundred thirty-seven thousand, six hundred sixty-one".