245021621 has 4 divisors (see below), whose sum is σ = 263869452. Its totient is φ = 226173792.

The previous prime is 245021593. The next prime is 245021627. The reversal of 245021621 is 126120542.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 126120542 = 2 ⋅63060271.

It can be written as a sum of positive squares in 2 ways, for example, as 144240100 + 100781521 = 12010^2 + 10039^2 .

It is a de Polignac number, because none of the positive numbers 2^k-245021621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (245021627) 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, 9423896 + ... + 9423921.

It is an arithmetic number, because the mean of its divisors is an integer number (65967363).

Almost surely, 2^245021621 is an apocalyptic number.

It is an amenable number.

245021621 is a deficient number, since it is larger than the sum of its proper divisors (18847831).

245021621 is a wasteful number, since it uses less digits than its factorization.

245021621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18847830.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 245021621 is about 15653.1664847723. The cubic root of 245021621 is about 625.7508807770.

The spelling of 245021621 in words is "two hundred forty-five million, twenty-one thousand, six hundred twenty-one".