81377253 has 6 divisors (see below), whose sum is σ = 117544934. Its totient is φ = 54251496.

The previous prime is 81377237. The next prime is 81377273. The reversal of 81377253 is 35277318.

It can be written as a sum of positive squares in only one way, i.e., 53846244 + 27531009 = 7338^2 + 5247^2 .

It is not a de Polignac number, because 81377253 - 2⁴ = 81377237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81377273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4520950 + ... + 4520967.

Almost surely, 2^81377253 is an apocalyptic number.

It is an amenable number.

81377253 is a deficient number, since it is larger than the sum of its proper divisors (36167681).

81377253 is a wasteful number, since it uses less digits than its factorization.

81377253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9041923 (or 9041920 counting only the distinct ones).

The product of its digits is 35280, while the sum is 36.

The square root of 81377253 is about 9020.9341534012. The cubic root of 81377253 is about 433.3455506746.

The spelling of 81377253 in words is "eighty-one million, three hundred seventy-seven thousand, two hundred fifty-three".