81513399 has 8 divisors (see below), whose sum is σ = 118564992. Its totient is φ = 49402040.

The previous prime is 81513379. The next prime is 81513427. The reversal of 81513399 is 99331518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81513399 - 2¹² = 81509303 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81513319) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1235019 + ... + 1235084.

It is an arithmetic number, because the mean of its divisors is an integer number (14820624).

Almost surely, 2^81513399 is an apocalyptic number.

81513399 is a deficient number, since it is larger than the sum of its proper divisors (37051593).

81513399 is a wasteful number, since it uses less digits than its factorization.

81513399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2470117.

The product of its digits is 29160, while the sum is 39.

The square root of 81513399 is about 9028.4771141096. The cubic root of 81513399 is about 433.5870816918.

The spelling of 81513399 in words is "eighty-one million, five hundred thirteen thousand, three hundred ninety-nine".