1187743721 has 16 divisors (see below), whose sum is σ = 1246924800. Its totient is φ = 1130227728.

The previous prime is 1187743663. The next prime is 1187743723. The reversal of 1187743721 is 1273477811.

1187743721 = 94² + 95² + ... + 1527².

It is a cyclic number.

It is not a de Polignac number, because 1187743721 - 2⁶ = 1187743657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1187743723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 481790 + ... + 484248.

It is an arithmetic number, because the mean of its divisors is an integer number (77932800).

Almost surely, 2^1187743721 is an apocalyptic number.

It is an amenable number.

1187743721 is a deficient number, since it is larger than the sum of its proper divisors (59181079).

1187743721 is a wasteful number, since it uses less digits than its factorization.

1187743721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2788.

The product of its digits is 65856, while the sum is 41.

The square root of 1187743721 is about 34463.6579747420. The cubic root of 1187743721 is about 1059.0283373649.

The spelling of 1187743721 in words is "one billion, one hundred eighty-seven million, seven hundred forty-three thousand, seven hundred twenty-one".