81002251 has 16 divisors (see below), whose sum is σ = 92971008. Its totient is φ = 69854400.

The previous prime is 81002237. The next prime is 81002261. The reversal of 81002251 is 15220018.

It is not a de Polignac number, because 81002251 - 2⁷ = 81002123 is a prime.

It is a super-2 number, since 2×81002251² = 13122729334134002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81002231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30871 + ... + 33391.

It is an arithmetic number, because the mean of its divisors is an integer number (5810688).

Almost surely, 2^81002251 is an apocalyptic number.

81002251 is a deficient number, since it is larger than the sum of its proper divisors (11968757).

81002251 is a wasteful number, since it uses less digits than its factorization.

81002251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2682.

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 81002251 is about 9000.1250546867. The cubic root of 81002251 is about 432.6788790845.

Adding to 81002251 its reverse (15220018), we get a palindrome (96222269).

The spelling of 81002251 in words is "eighty-one million, two thousand, two hundred fifty-one".