81292445 has 8 divisors (see below), whose sum is σ = 105054936. Its totient is φ = 60031296.

The previous prime is 81292439. The next prime is 81292483. The reversal of 81292445 is 54429218.

It can be written as a sum of positive squares in 4 ways, for example, as 18344089 + 62948356 = 4283^2 + 7934^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81292445 - 2¹² = 81288349 is a prime.

It is a super-2 number, since 2×81292445² = 13216923228156050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 625262 + ... + 625391.

It is an arithmetic number, because the mean of its divisors is an integer number (13131867).

Almost surely, 2^81292445 is an apocalyptic number.

It is an amenable number.

81292445 is a deficient number, since it is larger than the sum of its proper divisors (23762491).

81292445 is a wasteful number, since it uses less digits than its factorization.

81292445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1250671.

The product of its digits is 23040, while the sum is 35.

The square root of 81292445 is about 9016.2323062352. The cubic root of 81292445 is about 433.1949600925.

The spelling of 81292445 in words is "eighty-one million, two hundred ninety-two thousand, four hundred forty-five".