201521345 has 4 divisors (see below), whose sum is σ = 241825620. Its totient is φ = 161217072.

The previous prime is 201521311. The next prime is 201521381. The reversal of 201521345 is 543125102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 29203216 + 172318129 = 5404^2 + 13127^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201521345 is a prime.

It is a super-2 number, since 2×201521345² = 81221704981218050, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 201521345.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20152130 + ... + 20152139.

It is an arithmetic number, because the mean of its divisors is an integer number (60456405).

Almost surely, 2^201521345 is an apocalyptic number.

It is an amenable number.

201521345 is a deficient number, since it is larger than the sum of its proper divisors (40304275).

201521345 is an equidigital number, since it uses as much as digits as its factorization.

201521345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40304274.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 201521345 is about 14195.8213922267. The cubic root of 201521345 is about 586.2826169222.

Adding to 201521345 its reverse (543125102), we get a palindrome (744646447).

The spelling of 201521345 in words is "two hundred one million, five hundred twenty-one thousand, three hundred forty-five".