1200991 has 16 divisors (see below), whose sum is σ = 1410048. Its totient is φ = 1012000.

The previous prime is 1200989. The next prime is 1201001. The reversal of 1200991 is 1990021.

It is not a de Polignac number, because 1200991 - 2¹ = 1200989 is a prime.

It is a Duffinian number.

1200991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200191) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11841 + ... + 11941.

It is an arithmetic number, because the mean of its divisors is an integer number (88128).

2^1200991 is an apocalyptic number.

1200991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1200991 is a deficient number, since it is larger than the sum of its proper divisors (209057).

1200991 is a wasteful number, since it uses less digits than its factorization.

1200991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182.

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 1200991 is about 1095.8973492075. The cubic root of 1200991 is about 106.2951014983.

It can be divided in two parts, 12009 and 91, that added together give a square (12100 = 110²).

The spelling of 1200991 in words is "one million, two hundred thousand, nine hundred ninety-one".