81617490 has 32 divisors (see below), whose sum is σ = 217647360. Its totient is φ = 21764592.

The previous prime is 81617479. The next prime is 81617491. The reversal of 81617490 is 9471618.

81617490 is a `hidden beast` number, since 8 + 161 + 7 + 490 = 666.

It is a super-2 number, since 2×81617490² = 13322829347800200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81617491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 150874 + ... + 151413.

It is an arithmetic number, because the mean of its divisors is an integer number (6801480).

Almost surely, 2^81617490 is an apocalyptic number.

81617490 is an abundant number, since it is smaller than the sum of its proper divisors (136029870).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81617490 is a wasteful number, since it uses less digits than its factorization.

81617490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302303 (or 302297 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 81617490 is about 9034.2398684117. The cubic root of 81617490 is about 433.7715638995.

It can be divided in two parts, 8161 and 7490, that added together give a palindrome (15651).

The spelling of 81617490 in words is "eighty-one million, six hundred seventeen thousand, four hundred ninety".