81869659 has 4 divisors (see below), whose sum is σ = 82634904. Its totient is φ = 81104416.

The previous prime is 81869657. The next prime is 81869677. The reversal of 81869659 is 95696818.

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 81869659 - 2¹ = 81869657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81869657) 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, 382462 + ... + 382675.

It is an arithmetic number, because the mean of its divisors is an integer number (20658726).

Almost surely, 2^81869659 is an apocalyptic number.

81869659 is a deficient number, since it is larger than the sum of its proper divisors (765245).

81869659 is a wasteful number, since it uses less digits than its factorization.

81869659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765244.

The product of its digits is 933120, while the sum is 52.

The square root of 81869659 is about 9048.1853981890. The cubic root of 81869659 is about 434.2178378627.

It can be divided in two parts, 81869 and 659, that added together give a palindrome (82528).

The spelling of 81869659 in words is "eighty-one million, eight hundred sixty-nine thousand, six hundred fifty-nine".