81251033 has 4 divisors (see below), whose sum is σ = 81315840. Its totient is φ = 81186228.

The previous prime is 81251029. The next prime is 81251059. The reversal of 81251033 is 33015218.

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 81251033 - 2² = 81251029 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81250033) 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, 30485 + ... + 33042.

It is an arithmetic number, because the mean of its divisors is an integer number (20328960).

Almost surely, 2^81251033 is an apocalyptic number.

It is an amenable number.

81251033 is a deficient number, since it is larger than the sum of its proper divisors (64807).

81251033 is a wasteful number, since it uses less digits than its factorization.

81251033 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64806.

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

The square root of 81251033 is about 9013.9354890081. The cubic root of 81251033 is about 433.1213882011.

The spelling of 81251033 in words is "eighty-one million, two hundred fifty-one thousand, thirty-three".