81493436 has 12 divisors (see below), whose sum is σ = 145304712. Its totient is φ = 39977808.

The previous prime is 81493429. The next prime is 81493459. The reversal of 81493436 is 63439418.

It is a super-2 number, since 2×81493436² = 13282360222172192, 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 81493436.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 191990 + ... + 192413.

It is an arithmetic number, because the mean of its divisors is an integer number (12108726).

Almost surely, 2^81493436 is an apocalyptic number.

It is an amenable number.

81493436 is a deficient number, since it is larger than the sum of its proper divisors (63811276).

81493436 is a wasteful number, since it uses less digits than its factorization.

81493436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384460 (or 384458 counting only the distinct ones).

The product of its digits is 62208, while the sum is 38.

The square root of 81493436 is about 9027.3714889773. The cubic root of 81493436 is about 433.5516829896.

The spelling of 81493436 in words is "eighty-one million, four hundred ninety-three thousand, four hundred thirty-six".