81405194 has 16 divisors (see below), whose sum is σ = 135744000. Its totient is φ = 36359280.

The previous prime is 81405193. The next prime is 81405209. The reversal of 81405194 is 49150418.

It is a super-2 number, since 2×81405194² = 13253611220355272, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81405194.

It is not an unprimeable number, because it can be changed into a prime (81405193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49694 + ... + 51305.

It is an arithmetic number, because the mean of its divisors is an integer number (8484000).

Almost surely, 2^81405194 is an apocalyptic number.

81405194 is a deficient number, since it is larger than the sum of its proper divisors (54338806).

81405194 is a wasteful number, since it uses less digits than its factorization.

81405194 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101045.

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 81405194 is about 9022.4826960211. The cubic root of 81405194 is about 433.3951416109.

The spelling of 81405194 in words is "eighty-one million, four hundred five thousand, one hundred ninety-four".