81617461 has 4 divisors (see below), whose sum is σ = 81642924. Its totient is φ = 81592000.

The previous prime is 81617453. The next prime is 81617467. The reversal of 81617461 is 16471618.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16471618 = 2 ⋅8235809.

It can be written as a sum of positive squares in 2 ways, for example, as 55800900 + 25816561 = 7470^2 + 5081^2 .

It is a cyclic number.

It is not a de Polignac number, because 81617461 - 2³ = 81617453 is a prime.

It is a super-2 number, since 2×81617461² = 13322819880173042, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81617467) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7090 + ... + 14611.

It is an arithmetic number, because the mean of its divisors is an integer number (20410731).

Almost surely, 2^81617461 is an apocalyptic number.

It is an amenable number.

81617461 is a deficient number, since it is larger than the sum of its proper divisors (25463).

81617461 is a wasteful number, since it uses less digits than its factorization.

81617461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25462.

The product of its digits is 8064, while the sum is 34.

The square root of 81617461 is about 9034.2382634066. The cubic root of 81617461 is about 433.7715125242.

The spelling of 81617461 in words is "eighty-one million, six hundred seventeen thousand, four hundred sixty-one".