72166551 has 4 divisors (see below), whose sum is σ = 96222072. Its totient is φ = 48111032.

The previous prime is 72166489. The next prime is 72166553. The reversal of 72166551 is 15566127.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 72166551 - 2¹¹ = 72164503 is a prime.

It is a super-2 number, since 2×72166551² = 10416022166471202, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72166553) 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 3 ways as a sum of consecutive naturals, for example, 12027756 + ... + 12027761.

It is an arithmetic number, because the mean of its divisors is an integer number (24055518).

Almost surely, 2^72166551 is an apocalyptic number.

72166551 is a deficient number, since it is larger than the sum of its proper divisors (24055521).

72166551 is a wasteful number, since it uses less digits than its factorization.

72166551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24055520.

The product of its digits is 12600, while the sum is 33.

The square root of 72166551 is about 8495.0898170649. The cubic root of 72166551 is about 416.3372954014.

The spelling of 72166551 in words is "seventy-two million, one hundred sixty-six thousand, five hundred fifty-one".