1251521265 has 8 divisors (see below), whose sum is σ = 2002434048. Its totient is φ = 667478000.

The previous prime is 1251521251. The next prime is 1251521267. The reversal of 1251521265 is 5621251521.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1251521265 - 2⁵ = 1251521233 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1251521267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41717361 + ... + 41717390.

It is an arithmetic number, because the mean of its divisors is an integer number (250304256).

Almost surely, 2^1251521265 is an apocalyptic number.

1251521265 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1251521265 is a deficient number, since it is larger than the sum of its proper divisors (750912783).

1251521265 is an equidigital number, since it uses as much as digits as its factorization.

1251521265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83434759.

The product of its digits is 6000, while the sum is 30.

The square root of 1251521265 is about 35376.8464535775. The cubic root of 1251521265 is about 1077.6541633380.

Adding to 1251521265 its reverse (5621251521), we get a palindrome (6872772786).

The spelling of 1251521265 in words is "one billion, two hundred fifty-one million, five hundred twenty-one thousand, two hundred sixty-five".