81670741 has 4 divisors (see below), whose sum is σ = 82030752. Its totient is φ = 81310732.

The previous prime is 81670733. The next prime is 81670747. The reversal of 81670741 is 14707618.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81670741 - 2³ = 81670733 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81670697 and 81670706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81670747) 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, 179665 + ... + 180118.

It is an arithmetic number, because the mean of its divisors is an integer number (20507688).

Almost surely, 2^81670741 is an apocalyptic number.

It is an amenable number.

81670741 is a deficient number, since it is larger than the sum of its proper divisors (360011).

81670741 is a wasteful number, since it uses less digits than its factorization.

81670741 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360010.

The product of its (nonzero) digits is 9408, while the sum is 34.

The square root of 81670741 is about 9037.1865644126. The cubic root of 81670741 is about 433.8658808889.

The spelling of 81670741 in words is "eighty-one million, six hundred seventy thousand, seven hundred forty-one".