1251611245 has 4 divisors (see below), whose sum is σ = 1501933500. Its totient is φ = 1001288992.

The previous prime is 1251611243. The next prime is 1251611287. The reversal of 1251611245 is 5421161521.

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 813504484 + 438106761 = 28522^2 + 20931^2 .

It is a cyclic number.

It is not a de Polignac number, because 1251611245 - 2¹ = 1251611243 is a prime.

It is a super-2 number, since 2×1251611245² = 3133061417220900050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251611243) 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, 125161120 + ... + 125161129.

It is an arithmetic number, because the mean of its divisors is an integer number (375483375).

Almost surely, 2^1251611245 is an apocalyptic number.

It is an amenable number.

1251611245 is a deficient number, since it is larger than the sum of its proper divisors (250322255).

1251611245 is an equidigital number, since it uses as much as digits as its factorization.

1251611245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250322254.

The product of its digits is 2400, while the sum is 28.

The square root of 1251611245 is about 35378.1181664599. The cubic root of 1251611245 is about 1077.6799892403.

Adding to 1251611245 its reverse (5421161521), we get a palindrome (6672772766).

The spelling of 1251611245 in words is "one billion, two hundred fifty-one million, six hundred eleven thousand, two hundred forty-five".