1251722201 has 4 divisors (see below), whose sum is σ = 1260011904. Its totient is φ = 1243432500.

The previous prime is 1251722141. The next prime is 1251722209. The reversal of 1251722201 is 1022271521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1022271521 = 673 ⋅1518977.

It is a cyclic number.

It is not a de Polignac number, because 1251722201 - 2²⁶ = 1184613337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1251722209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4144625 + ... + 4144926.

It is an arithmetic number, because the mean of its divisors is an integer number (315002976).

Almost surely, 2^1251722201 is an apocalyptic number.

It is an amenable number.

1251722201 is a deficient number, since it is larger than the sum of its proper divisors (8289703).

1251722201 is an equidigital number, since it uses as much as digits as its factorization.

1251722201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8289702.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 1251722201 is about 35379.6862761670. The cubic root of 1251722201 is about 1077.7118339333.

Adding to 1251722201 its reverse (1022271521), we get a palindrome (2273993722).

The spelling of 1251722201 in words is "one billion, two hundred fifty-one million, seven hundred twenty-two thousand, two hundred one".