1187146721 has 4 divisors (see below), whose sum is σ = 1194255552. Its totient is φ = 1180037892.

The previous prime is 1187146711. The next prime is 1187146747. The reversal of 1187146721 is 1276417811.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1276417811 = 2647 ⋅482213.

It is a cyclic number.

It is not a de Polignac number, because 1187146721 - 2¹⁸ = 1186884577 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1187146711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3554165 + ... + 3554498.

It is an arithmetic number, because the mean of its divisors is an integer number (298563888).

Almost surely, 2^1187146721 is an apocalyptic number.

It is an amenable number.

1187146721 is a deficient number, since it is larger than the sum of its proper divisors (7108831).

1187146721 is an equidigital number, since it uses as much as digits as its factorization.

1187146721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7108830.

The product of its digits is 18816, while the sum is 38.

The square root of 1187146721 is about 34454.9955884484. The cubic root of 1187146721 is about 1058.8508731908.

The spelling of 1187146721 in words is "one billion, one hundred eighty-seven million, one hundred forty-six thousand, seven hundred twenty-one".