1191420500 has 48 divisors (see below), whose sum is σ = 2621206224. Its totient is φ = 473062400.

The previous prime is 1191420499. The next prime is 1191420509. The reversal of 1191420500 is 50241911.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 506970256 + 684450244 = 22516^2 + 26162^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1191420509) 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, 59804 + ... + 77196.

It is an arithmetic number, because the mean of its divisors is an integer number (54608463).

Almost surely, 2^1191420500 is an apocalyptic number.

1191420500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1191420500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1310603112).

1191420500 is an abundant number, since it is smaller than the sum of its proper divisors (1429785724).

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

1191420500 is a wasteful number, since it uses less digits than its factorization.

1191420500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17549 (or 17537 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 1191420500 is about 34516.9595995939. The cubic root of 1191420500 is about 1060.1199876041.

The spelling of 1191420500 in words is "one billion, one hundred ninety-one million, four hundred twenty thousand, five hundred".