1191990 has 16 divisors (see below), whose sum is σ = 2860848. Its totient is φ = 317856.

The previous prime is 1191979. The next prime is 1191991. The reversal of 1191990 is 991911.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 39733 = 1191990 / (1 + 1 + 9 + 1 + 9 + 9 + 0).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1191991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19837 + ... + 19896.

It is an arithmetic number, because the mean of its divisors is an integer number (178803).

2^1191990 is an apocalyptic number.

1191990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1191990 is an abundant number, since it is smaller than the sum of its proper divisors (1668858).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1191990 is a wasteful number, since it uses less digits than its factorization.

1191990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39743.

The product of its (nonzero) digits is 729, while the sum is 30.

The square root of 1191990 is about 1091.7829454612. The cubic root of 1191990 is about 106.0288873446.

The spelling of 1191990 in words is "one million, one hundred ninety-one thousand, nine hundred ninety".