81956953 has 4 divisors (see below), whose sum is σ = 88261348. Its totient is φ = 75652560.

The previous prime is 81956923. The next prime is 81956957. The reversal of 81956953 is 35965918.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12201049 + 69755904 = 3493^2 + 8352^2 .

It is a cyclic number.

It is not a de Polignac number, because 81956953 - 2²⁵ = 48402521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81956957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3152178 + ... + 3152203.

It is an arithmetic number, because the mean of its divisors is an integer number (22065337).

Almost surely, 2^81956953 is an apocalyptic number.

It is an amenable number.

81956953 is a deficient number, since it is larger than the sum of its proper divisors (6304395).

81956953 is a wasteful number, since it uses less digits than its factorization.

81956953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6304394.

The product of its digits is 291600, while the sum is 46.

The square root of 81956953 is about 9053.0079531612. The cubic root of 81956953 is about 434.3721121420.

The spelling of 81956953 in words is "eighty-one million, nine hundred fifty-six thousand, nine hundred fifty-three".