72105551 has 16 divisors (see below), whose sum is σ = 91848960. Its totient is φ = 55105920.

The previous prime is 72105533. The next prime is 72105557. The reversal of 72105551 is 15550127.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 72105551 - 2¹⁸ = 71843407 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 72105551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72105557) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13685 + ... + 18206.

It is an arithmetic number, because the mean of its divisors is an integer number (5740560).

Almost surely, 2^72105551 is an apocalyptic number.

72105551 is a deficient number, since it is larger than the sum of its proper divisors (19743409).

72105551 is a wasteful number, since it uses less digits than its factorization.

72105551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31934.

The product of its (nonzero) digits is 1750, while the sum is 26.

The square root of 72105551 is about 8491.4987487487. The cubic root of 72105551 is about 416.2199569500.

Adding to 72105551 its reverse (15550127), we get a palindrome (87655678).

The spelling of 72105551 in words is "seventy-two million, one hundred five thousand, five hundred fifty-one".