4251522521 has 4 divisors (see below), whose sum is σ = 4255576500. Its totient is φ = 4247468544.

The previous prime is 4251522449. The next prime is 4251522553. The reversal of 4251522521 is 1252251524.

It is a happy number.

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 3765540496 + 485982025 = 61364^2 + 22045^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4251522521 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (4251522421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2025416 + ... + 2027513.

It is an arithmetic number, because the mean of its divisors is an integer number (1063894125).

Almost surely, 2^4251522521 is an apocalyptic number.

It is an amenable number.

4251522521 is a deficient number, since it is larger than the sum of its proper divisors (4053979).

4251522521 is a wasteful number, since it uses less digits than its factorization.

4251522521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4053978.

The product of its digits is 8000, while the sum is 29.

The square root of 4251522521 is about 65203.7002094206. The cubic root of 4251522521 is about 1619.9993040946. Note that the first 3 decimals are identical.

The spelling of 4251522521 in words is "four billion, two hundred fifty-one million, five hundred twenty-two thousand, five hundred twenty-one".