81403437 has 4 divisors (see below), whose sum is σ = 108537920. Its totient is φ = 54268956.

The previous prime is 81403433. The next prime is 81403447. The reversal of 81403437 is 73430418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81403437 - 2² = 81403433 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81403433) 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, 13567237 + ... + 13567242.

It is an arithmetic number, because the mean of its divisors is an integer number (27134480).

Almost surely, 2^81403437 is an apocalyptic number.

It is an amenable number.

81403437 is a deficient number, since it is larger than the sum of its proper divisors (27134483).

81403437 is a wasteful number, since it uses less digits than its factorization.

81403437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27134482.

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 81403437 is about 9022.3853276171. The cubic root of 81403437 is about 433.3920235431.

The spelling of 81403437 in words is "eighty-one million, four hundred three thousand, four hundred thirty-seven".