81070551 has 20 divisors (see below), whose sum is σ = 121387200. Its totient is φ = 53921376.

The previous prime is 81070537. The next prime is 81070559. The reversal of 81070551 is 15507018.

81070551 is a `hidden beast` number, since 8 + 107 + 0 + 551 = 666.

It is not a de Polignac number, because 81070551 - 2⁵ = 81070519 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81070559) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 45210 + ... + 46968.

It is an arithmetic number, because the mean of its divisors is an integer number (6069360).

Almost surely, 2^81070551 is an apocalyptic number.

81070551 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81070551 is a deficient number, since it is larger than the sum of its proper divisors (40316649).

81070551 is a wasteful number, since it uses less digits than its factorization.

81070551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2340 (or 2331 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 27.

The square root of 81070551 is about 9003.9186469004. The cubic root of 81070551 is about 432.8004545758.

Adding to 81070551 its reverse (15507018), we get a palindrome (96577569).

The spelling of 81070551 in words is "eighty-one million, seventy thousand, five hundred fifty-one".