81825405 has 16 divisors (see below), whose sum is σ = 131212224. Its totient is φ = 43543040.

The previous prime is 81825397. The next prime is 81825413. The reversal of 81825405 is 50452818.

It is an interprime number because it is at equal distance from previous prime (81825397) and next prime (81825413).

It is not a de Polignac number, because 81825405 - 2³ = 81825397 is a prime.

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, 1165 + ... + 12845.

It is an arithmetic number, because the mean of its divisors is an integer number (8200764).

Almost surely, 2^81825405 is an apocalyptic number.

It is an amenable number.

81825405 is a deficient number, since it is larger than the sum of its proper divisors (49386819).

81825405 is a wasteful number, since it uses less digits than its factorization.

81825405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12156.

The product of its (nonzero) digits is 12800, while the sum is 33.

The square root of 81825405 is about 9045.7396049190. The cubic root of 81825405 is about 434.1395860830.

The spelling of 81825405 in words is "eighty-one million, eight hundred twenty-five thousand, four hundred five".