102209581 has 4 divisors (see below), whose sum is σ = 104586592. Its totient is φ = 99832572.

The previous prime is 102209567. The next prime is 102209617. The reversal of 102209581 is 185902201.

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, and also an emirpimes, since its reverse is a distinct semiprime: 185902201 = 43 ⋅4323307.

It is a cyclic number.

It is not a de Polignac number, because 102209581 - 2⁷ = 102209453 is a prime.

It is a super-2 number, since 2×102209581² = 20893596896391122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102209501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1188441 + ... + 1188526.

It is an arithmetic number, because the mean of its divisors is an integer number (26146648).

Almost surely, 2^102209581 is an apocalyptic number.

It is an amenable number.

102209581 is a deficient number, since it is larger than the sum of its proper divisors (2377011).

102209581 is an equidigital number, since it uses as much as digits as its factorization.

102209581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2377010.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 102209581 is about 10109.8754196083. The cubic root of 102209581 is about 467.5526641463.

The spelling of 102209581 in words is "one hundred two million, two hundred nine thousand, five hundred eighty-one".