81213803 has 4 divisors (see below), whose sum is σ = 88596888. Its totient is φ = 73830720.

The previous prime is 81213787. The next prime is 81213857. The reversal of 81213803 is 30831218.

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

It is a cyclic number.

It is not a de Polignac number, because 81213803 - 2⁴ = 81213787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81213103) 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, 3691526 + ... + 3691547.

It is an arithmetic number, because the mean of its divisors is an integer number (22149222).

Almost surely, 2^81213803 is an apocalyptic number.

81213803 is a deficient number, since it is larger than the sum of its proper divisors (7383085).

81213803 is a wasteful number, since it uses less digits than its factorization.

81213803 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7383084.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 81213803 is about 9011.8701166850. The cubic root of 81213803 is about 433.0552246411.

The spelling of 81213803 in words is "eighty-one million, two hundred thirteen thousand, eight hundred three".