81290450 has 12 divisors (see below), whose sum is σ = 151200330. Its totient is φ = 32516160.

The previous prime is 81290437. The next prime is 81290453. The reversal of 81290450 is 5409218.

It can be written as a sum of positive squares in 3 ways, for example, as 70274689 + 11015761 = 8383^2 + 3319^2 .

It is a super-2 number, since 2×81290450² = 13216274522405000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81290453) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 812855 + ... + 812954.

Almost surely, 2^81290450 is an apocalyptic number.

81290450 is a deficient number, since it is larger than the sum of its proper divisors (69909880).

81290450 is a wasteful number, since it uses less digits than its factorization.

81290450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1625821 (or 1625816 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 81290450 is about 9016.1216717611. The cubic root of 81290450 is about 433.1914163806.

Adding to 81290450 its reverse (5409218), we get a palindrome (86699668).

The spelling of 81290450 in words is "eighty-one million, two hundred ninety thousand, four hundred fifty".