253166821 has 4 divisors (see below), whose sum is σ = 255014892. Its totient is φ = 251318752.

The previous prime is 253166807. The next prime is 253166831. The reversal of 253166821 is 128661352.

253166821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 53085796 + 200081025 = 7286^2 + 14145^2 .

It is a cyclic number.

It is not a de Polignac number, because 253166821 - 2²¹ = 251069669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (253166831) 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, 923830 + ... + 924103.

It is an arithmetic number, because the mean of its divisors is an integer number (63753723).

Almost surely, 2^253166821 is an apocalyptic number.

It is an amenable number.

253166821 is a deficient number, since it is larger than the sum of its proper divisors (1848071).

253166821 is a wasteful number, since it uses less digits than its factorization.

253166821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1848070.

The product of its digits is 17280, while the sum is 34.

The square root of 253166821 is about 15911.2168296457. The cubic root of 253166821 is about 632.6093347838.

The spelling of 253166821 in words is "two hundred fifty-three million, one hundred sixty-six thousand, eight hundred twenty-one".