1251609 has 4 divisors (see below), whose sum is σ = 1668816. Its totient is φ = 834404.

The previous prime is 1251583. The next prime is 1251641. The reversal of 1251609 is 9061521.

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.

It is a cyclic number.

It is not a de Polignac number, because 1251609 - 2⁵ = 1251577 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (1251109) 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, 208599 + ... + 208604.

It is an arithmetic number, because the mean of its divisors is an integer number (417204).

2^1251609 is an apocalyptic number.

It is an amenable number.

1251609 is a deficient number, since it is larger than the sum of its proper divisors (417207).

1251609 is an equidigital number, since it uses as much as digits as its factorization.

1251609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417206.

The product of its (nonzero) digits is 540, while the sum is 24.

The square root of 1251609 is about 1118.7533240174. The cubic root of 1251609 is about 107.7679344899.

The spelling of 1251609 in words is "one million, two hundred fifty-one thousand, six hundred nine".