83521665 has 16 divisors (see below), whose sum is σ = 148483200. Its totient is φ = 44544816.

The previous prime is 83521661. The next prime is 83521673. The reversal of 83521665 is 56612538.

It is not a de Polignac number, because 83521665 - 2² = 83521661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (83521661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 309205 + ... + 309474.

It is an arithmetic number, because the mean of its divisors is an integer number (9280200).

Almost surely, 2^83521665 is an apocalyptic number.

It is an amenable number.

83521665 is a deficient number, since it is larger than the sum of its proper divisors (64961535).

83521665 is a wasteful number, since it uses less digits than its factorization.

83521665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618693 (or 618687 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 83521665 is about 9139.0188204205. The cubic root of 83521665 is about 437.1190305298.

It can be divided in two parts, 835 and 21665, that added together give a square (22500 = 150²).

The spelling of 83521665 in words is "eighty-three million, five hundred twenty-one thousand, six hundred sixty-five".