81405433 has 4 divisors (see below), whose sum is σ = 81425268. Its totient is φ = 81385600.

The previous prime is 81405431. The next prime is 81405449. The reversal of 81405433 is 33450418.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 49449024 + 31956409 = 7032^2 + 5653^2 .

It is a cyclic number.

It is not a de Polignac number, because 81405433 - 2¹ = 81405431 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81405431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1216 + ... + 12817.

It is an arithmetic number, because the mean of its divisors is an integer number (20356317).

Almost surely, 2^81405433 is an apocalyptic number.

It is an amenable number.

81405433 is a deficient number, since it is larger than the sum of its proper divisors (19835).

81405433 is a wasteful number, since it uses less digits than its factorization.

81405433 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19834.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 81405433 is about 9022.4959407029. The cubic root of 81405433 is about 433.3955657499.

The spelling of 81405433 in words is "eighty-one million, four hundred five thousand, four hundred thirty-three".