1211391 has 12 divisors (see below), whose sum is σ = 1759680. Its totient is φ = 803040.

The previous prime is 1211389. The next prime is 1211393. The reversal of 1211391 is 1931121.

It is an interprime number because it is at equal distance from previous prime (1211389) and next prime (1211393).

It is not a de Polignac number, because 1211391 - 2¹ = 1211389 is a prime.

It is a super-3 number, since 3×1211391³ = 5333033146828348413, which contains 333 as substring.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211393) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2290 + ... + 2768.

It is an arithmetic number, because the mean of its divisors is an integer number (146640).

2^1211391 is an apocalyptic number.

1211391 is a deficient number, since it is larger than the sum of its proper divisors (548289).

1211391 is a wasteful number, since it uses less digits than its factorization.

1211391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 766 (or 763 counting only the distinct ones).

The product of its digits is 54, while the sum is 18.

The square root of 1211391 is about 1100.6320911186. The cubic root of 1211391 is about 106.6010414475.

The spelling of 1211391 in words is "one million, two hundred eleven thousand, three hundred ninety-one".