81738503989 has 4 divisors (see below), whose sum is σ = 81740345056. Its totient is φ = 81736662924.

The previous prime is 81738503983. The next prime is 81738504037. The reversal of 81738503989 is 98930583718.

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 a cyclic number.

It is not a de Polignac number, because 81738503989 - 2⁹ = 81738503477 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 (81738503983) 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, 852249 + ... + 943294.

It is an arithmetic number, because the mean of its divisors is an integer number (20435086264).

Almost surely, 2^81738503989 is an apocalyptic number.

It is an amenable number.

81738503989 is a deficient number, since it is larger than the sum of its proper divisors (1841067).

81738503989 is a wasteful number, since it uses less digits than its factorization.

81738503989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1841066.

The product of its (nonzero) digits is 13063680, while the sum is 61.

The spelling of 81738503989 in words is "eighty-one billion, seven hundred thirty-eight million, five hundred three thousand, nine hundred eighty-nine".