72106665 has 16 divisors (see below), whose sum is σ = 116762688. Its totient is φ = 37992896.

The previous prime is 72106631. The next prime is 72106693. The reversal of 72106665 is 56660127.

It is a cyclic number.

It is not a de Polignac number, because 72106665 - 2¹³ = 72098473 is a prime.

It is a super-2 number, since 2×72106665² = 10398742274844450, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27714 + ... + 30203.

It is an arithmetic number, because the mean of its divisors is an integer number (7297668).

Almost surely, 2^72106665 is an apocalyptic number.

It is an amenable number.

72106665 is a deficient number, since it is larger than the sum of its proper divisors (44656023).

72106665 is a wasteful number, since it uses less digits than its factorization.

72106665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58008.

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 72106665 is about 8491.5643435117. The cubic root of 72106665 is about 416.2221004125. Note that the first 3 decimals are identical.

It can be divided in two parts, 72106 and 665, that added together give a triangular number (72771 = T₃₈₁).

The spelling of 72106665 in words is "seventy-two million, one hundred six thousand, six hundred sixty-five".