1251605 has 8 divisors (see below), whose sum is σ = 1510872. Its totient is φ = 995328.

The previous prime is 1251583. The next prime is 1251641. The reversal of 1251605 is 5061521.

It can be written as a sum of positive squares in 4 ways, for example, as 343396 + 908209 = 586^2 + 953^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 1251605 - 2¹² = 1247509 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 317 + ... + 1613.

It is an arithmetic number, because the mean of its divisors is an integer number (188859).

2^1251605 is an apocalyptic number.

It is an amenable number.

1251605 is a deficient number, since it is larger than the sum of its proper divisors (259267).

1251605 is a wasteful number, since it uses less digits than its factorization.

1251605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1495.

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 1251605 is about 1118.7515363118. The cubic root of 1251605 is about 107.7678196851.

The spelling of 1251605 in words is "one million, two hundred fifty-one thousand, six hundred five".