81670040 has 32 divisors (see below), whose sum is σ = 194568480. Its totient is φ = 30746112.

The previous prime is 81670031. The next prime is 81670051. The reversal of 81670040 is 4007618.

It is a Smith number, since the sum of its digits (26) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 81669991 and 81670009.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59372 + ... + 60731.

It is an arithmetic number, because the mean of its divisors is an integer number (6080265).

Almost surely, 2^81670040 is an apocalyptic number.

It is an amenable number.

81670040 is an abundant number, since it is smaller than the sum of its proper divisors (112898440).

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

81670040 is a wasteful number, since it uses less digits than its factorization.

81670040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120131 (or 120127 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 81670040 is about 9037.1477801351. The cubic root of 81670040 is about 433.8646395596.

Adding to 81670040 its reverse (4007618), we get a palindrome (85677658).

The spelling of 81670040 in words is "eighty-one million, six hundred seventy thousand, forty".