81490228 has 6 divisors (see below), whose sum is σ = 142607906. Its totient is φ = 40745112.

The previous prime is 81490223. The next prime is 81490229. The reversal of 81490228 is 82209418.

It can be written as a sum of positive squares in only one way, i.e., 76772644 + 4717584 = 8762^2 + 2172^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81490193 and 81490202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81490223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10186275 + ... + 10186282.

Almost surely, 2^81490228 is an apocalyptic number.

It is an amenable number.

81490228 is a deficient number, since it is larger than the sum of its proper divisors (61117678).

81490228 is a wasteful number, since it uses less digits than its factorization.

81490228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20372561 (or 20372559 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 81490228 is about 9027.1938053860. The cubic root of 81490228 is about 433.5459939749.

It can be divided in two parts, 81490 and 228, that added together give a palindrome (81718).

The spelling of 81490228 in words is "eighty-one million, four hundred ninety thousand, two hundred twenty-eight".