72166908761 has 4 divisors (see below), whose sum is σ = 72214294992. Its totient is φ = 72119522532.

The previous prime is 72166908739. The next prime is 72166908767. The reversal of 72166908761 is 16780966127.

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: 16780966127 = 67 ⋅250462181.

It is a cyclic number.

It is not a de Polignac number, because 72166908761 - 2¹⁴ = 72166892377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72166908767) 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, 23690831 + ... + 23693876.

It is an arithmetic number, because the mean of its divisors is an integer number (18053573748).

Almost surely, 2^72166908761 is an apocalyptic number.

It is an amenable number.

72166908761 is a deficient number, since it is larger than the sum of its proper divisors (47386231).

72166908761 is a wasteful number, since it uses less digits than its factorization.

72166908761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47386230.

The product of its (nonzero) digits is 1524096, while the sum is 53.

The spelling of 72166908761 in words is "seventy-two billion, one hundred sixty-six million, nine hundred eight thousand, seven hundred sixty-one".