81000070 has 64 divisors (see below), whose sum is σ = 160543296. Its totient is φ = 29306880.

The previous prime is 81000061. The next prime is 81000071. The reversal of 81000070 is 7000018.

It is a super-2 number, since 2×81000070² = 13122022680009800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81000071) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 756957 + ... + 757063.

It is an arithmetic number, because the mean of its divisors is an integer number (2508489).

Almost surely, 2^81000070 is an apocalyptic number.

81000070 is a deficient number, since it is larger than the sum of its proper divisors (79543226).

81000070 is a wasteful number, since it uses less digits than its factorization.

81000070 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 81000070 is about 9000.0038888880. The cubic root of 81000070 is about 432.6749957310.

Adding to 81000070 its reverse (7000018), we get a palindrome (88000088).

The spelling of 81000070 in words is "eighty-one million, seventy", and thus it is an aban number and an uban number.