2251026721 has 6 divisors (see below), whose sum is σ = 2353153250. Its totient is φ = 2153155488.

The previous prime is 2251026709. The next prime is 2251026727. The reversal of 2251026721 is 1276201522.

It can be written as a sum of positive squares in only one way, i.e., 1700655121 + 550371600 = 41239^2 + 23460^2 .

It is not a de Polignac number, because 2251026721 - 2¹³ = 2251018529 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2251026721.

It is not an unprimeable number, because it can be changed into a prime (2251026727) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2127096 + ... + 2128153.

Almost surely, 2^2251026721 is an apocalyptic number.

It is an amenable number.

2251026721 is a deficient number, since it is larger than the sum of its proper divisors (102126529).

2251026721 is an equidigital number, since it uses as much as digits as its factorization.

2251026721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4255295 (or 4255272 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 2251026721 is about 47444.9862577702. The cubic root of 2251026721 is about 1310.5699831077.

The spelling of 2251026721 in words is "two billion, two hundred fifty-one million, twenty-six thousand, seven hundred twenty-one".