1215851 has 16 divisors (see below), whose sum is σ = 1548288. Its totient is φ = 928800.

The previous prime is 1215847. The next prime is 1215853. The reversal of 1215851 is 1585121.

It is a cyclic number.

It is not a de Polignac number, because 1215851 - 2² = 1215847 is a prime.

It is a Smith number, since the sum of its digits (23) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (1215853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2606 + ... + 3036.

It is an arithmetic number, because the mean of its divisors is an integer number (96768).

2^1215851 is an apocalyptic number.

1215851 is a deficient number, since it is larger than the sum of its proper divisors (332437).

1215851 is a wasteful number, since it uses less digits than its factorization.

1215851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 482.

The product of its digits is 400, while the sum is 23.

The square root of 1215851 is about 1102.6563381217. The cubic root of 1215851 is about 106.7317062111.

The spelling of 1215851 in words is "one million, two hundred fifteen thousand, eight hundred fifty-one".