245404021 has 4 divisors (see below), whose sum is σ = 247575852. Its totient is φ = 243232192.

The previous prime is 245404007. The next prime is 245404063. The reversal of 245404021 is 120404542.

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 13176900 + 232227121 = 3630^2 + 15239^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-245404021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 245403983 and 245404001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (245404421) 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, 1085746 + ... + 1085971.

It is an arithmetic number, because the mean of its divisors is an integer number (61893963).

Almost surely, 2^245404021 is an apocalyptic number.

It is an amenable number.

245404021 is a deficient number, since it is larger than the sum of its proper divisors (2171831).

245404021 is a wasteful number, since it uses less digits than its factorization.

245404021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2171830.

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 245404021 is about 15665.3765036146. The cubic root of 245404021 is about 626.0762435758.

Adding to 245404021 its reverse (120404542), we get a palindrome (365808563).

It can be divided in two parts, 24540 and 4021, that added together give a 4-th power (28561 = 13⁴).

The spelling of 245404021 in words is "two hundred forty-five million, four hundred four thousand, twenty-one".