72671661 has 20 divisors (see below), whose sum is σ = 108791100. Its totient is φ = 48344256.

The previous prime is 72671659. The next prime is 72671671. The reversal of 72671661 is 16617627.

It can be written as a sum of positive squares in 2 ways, for example, as 28196100 + 44475561 = 5310^2 + 6669^2 .

It is not a de Polignac number, because 72671661 - 2¹ = 72671659 is a prime.

It is a super-3 number, since 3×72671661³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72671611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 64975 + ... + 66083.

It is an arithmetic number, because the mean of its divisors is an integer number (5439555).

Almost surely, 2^72671661 is an apocalyptic number.

It is an amenable number.

72671661 is a deficient number, since it is larger than the sum of its proper divisors (36119439).

72671661 is a wasteful number, since it uses less digits than its factorization.

72671661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1930 (or 1921 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 72671661 is about 8524.7675041610. The cubic root of 72671661 is about 417.3063842226.

The spelling of 72671661 in words is "seventy-two million, six hundred seventy-one thousand, six hundred sixty-one".