81629555 has 16 divisors (see below), whose sum is σ = 112981440. Its totient is φ = 55458432.

The previous prime is 81629533. The next prime is 81629579. The reversal of 81629555 is 55592618.

It is a cyclic number.

It is not a de Polignac number, because 81629555 - 2¹⁴ = 81613171 is a prime.

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, 6884 + ... + 14513.

It is an arithmetic number, because the mean of its divisors is an integer number (7061340).

Almost surely, 2^81629555 is an apocalyptic number.

81629555 is a deficient number, since it is larger than the sum of its proper divisors (31351885).

81629555 is a wasteful number, since it uses less digits than its factorization.

81629555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21518.

The product of its digits is 108000, while the sum is 41.

The square root of 81629555 is about 9034.9075811543. The cubic root of 81629555 is about 433.7929367534.

The spelling of 81629555 in words is "eighty-one million, six hundred twenty-nine thousand, five hundred fifty-five".