81606610 has 16 divisors (see below), whose sum is σ = 147004056. Its totient is φ = 32617728.

The previous prime is 81606607. The next prime is 81606611. The reversal of 81606610 is 1660618.

It can be written as a sum of positive squares in 4 ways, for example, as 69405561 + 12201049 = 8331^2 + 3493^2 .

It is not an unprimeable number, because it can be changed into a prime (81606611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16552 + ... + 20908.

Almost surely, 2^81606610 is an apocalyptic number.

81606610 is a deficient number, since it is larger than the sum of its proper divisors (65397446).

81606610 is a wasteful number, since it uses less digits than its factorization.

81606610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6237.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 81606610 is about 9033.6376947496. The cubic root of 81606610 is about 433.7522884381.

The spelling of 81606610 in words is "eighty-one million, six hundred six thousand, six hundred ten".