81212885 has 16 divisors (see below), whose sum is σ = 109517184. Its totient is φ = 57364032.

The previous prime is 81212863. The next prime is 81212933. The reversal of 81212885 is 58821218.

It is a cyclic number.

It is not a de Polignac number, because 81212885 - 2¹⁴ = 81196501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25667 + ... + 28656.

It is an arithmetic number, because the mean of its divisors is an integer number (6844824).

Almost surely, 2^81212885 is an apocalyptic number.

It is an amenable number.

81212885 is a deficient number, since it is larger than the sum of its proper divisors (28304299).

81212885 is a wasteful number, since it uses less digits than its factorization.

81212885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54364.

The product of its digits is 10240, while the sum is 35.

The square root of 81212885 is about 9011.8191837165. The cubic root of 81212885 is about 433.0535929554.

The spelling of 81212885 in words is "eighty-one million, two hundred twelve thousand, eight hundred eighty-five".