81000356 has 6 divisors (see below), whose sum is σ = 141750630. Its totient is φ = 40500176.

The previous prime is 81000343. The next prime is 81000371. The reversal of 81000356 is 65300018.

It can be written as a sum of positive squares in only one way, i.e., 68326756 + 12673600 = 8266^2 + 3560^2 .

It is a super-2 number, since 2×81000356² = 13122115344253472, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10125041 + ... + 10125048.

It is an arithmetic number, because the mean of its divisors is an integer number (23625105).

Almost surely, 2^81000356 is an apocalyptic number.

It is an amenable number.

81000356 is a deficient number, since it is larger than the sum of its proper divisors (60750274).

81000356 is a wasteful number, since it uses less digits than its factorization.

81000356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20250093 (or 20250091 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 81000356 is about 9000.0197777560. The cubic root of 81000356 is about 432.6755049689.

The spelling of 81000356 in words is "eighty-one million, three hundred fifty-six", and thus it is an aban number.