245542021 has 4 divisors (see below), whose sum is σ = 245830732. Its totient is φ = 245253312.

The previous prime is 245542007. The next prime is 245542051. The reversal of 245542021 is 120245542.

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 90041121 + 155500900 = 9489^2 + 12470^2 .

It is a cyclic number.

It is not a de Polignac number, because 245542021 - 2²¹ = 243444869 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 (245542051) 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, 143076 + ... + 144781.

It is an arithmetic number, because the mean of its divisors is an integer number (61457683).

Almost surely, 2^245542021 is an apocalyptic number.

It is an amenable number.

245542021 is a deficient number, since it is larger than the sum of its proper divisors (288711).

245542021 is an equidigital number, since it uses as much as digits as its factorization.

245542021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288710.

The product of its (nonzero) digits is 3200, while the sum is 25.

The square root of 245542021 is about 15669.7805026107. The cubic root of 245542021 is about 626.1935770670.

Adding to 245542021 its reverse (120245542), we get a palindrome (365787563).

The spelling of 245542021 in words is "two hundred forty-five million, five hundred forty-two thousand, twenty-one".