1187643820 has 24 divisors (see below), whose sum is σ = 2720784528. Its totient is φ = 431870400.

The previous prime is 1187643791. The next prime is 1187643829. The reversal of 1187643820 is 283467811.

It is not an unprimeable number, because it can be changed into a prime (1187643829) 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, 2698971 + ... + 2699410.

It is an arithmetic number, because the mean of its divisors is an integer number (113366022).

Almost surely, 2^1187643820 is an apocalyptic number.

1187643820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1187643820 is an abundant number, since it is smaller than the sum of its proper divisors (1533140708).

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

1187643820 is a wasteful number, since it uses less digits than its factorization.

1187643820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5398401 (or 5398399 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 40.

The square root of 1187643820 is about 34462.2085769325. The cubic root of 1187643820 is about 1058.9986449448.

It can be divided in two parts, 11876 and 43820, that added together give a square (55696 = 236²).

The spelling of 1187643820 in words is "one billion, one hundred eighty-seven million, six hundred forty-three thousand, eight hundred twenty".