81002551 has 16 divisors (see below), whose sum is σ = 94348800. Its totient is φ = 68110560.

The previous prime is 81002543. The next prime is 81002561. The reversal of 81002551 is 15520018.

It is not a de Polignac number, because 81002551 - 2³ = 81002543 is a prime.

It is a super-2 number, since 2×81002551² = 13122826537015202, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81002521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 173220 + ... + 173686.

It is an arithmetic number, because the mean of its divisors is an integer number (5896800).

Almost surely, 2^81002551 is an apocalyptic number.

81002551 is a deficient number, since it is larger than the sum of its proper divisors (13346249).

81002551 is a wasteful number, since it uses less digits than its factorization.

81002551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 894.

The product of its (nonzero) digits is 400, while the sum is 22.

The square root of 81002551 is about 9000.1417211064. The cubic root of 81002551 is about 432.6794132404.

Adding to 81002551 its reverse (15520018), we get a palindrome (96522569).

The spelling of 81002551 in words is "eighty-one million, two thousand, five hundred fifty-one".