1187038981 has 4 divisors (see below), whose sum is σ = 1193900652. Its totient is φ = 1180177312.

The previous prime is 1187038969. The next prime is 1187038999. The reversal of 1187038981 is 1898307811.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1898307811 = 5483 ⋅346217.

It can be written as a sum of positive squares in 2 ways, for example, as 858197025 + 328841956 = 29295^2 + 18134^2 .

It is a cyclic number.

It is not a de Polignac number, because 1187038981 - 2²³ = 1178650373 is a prime.

It is a super-2 number, since 2×1187038981² = 2818123084827036722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1187038681) 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, 3430576 + ... + 3430921.

It is an arithmetic number, because the mean of its divisors is an integer number (298475163).

Almost surely, 2^1187038981 is an apocalyptic number.

It is an amenable number.

1187038981 is a deficient number, since it is larger than the sum of its proper divisors (6861671).

1187038981 is an equidigital number, since it uses as much as digits as its factorization.

1187038981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6861670.

The product of its (nonzero) digits is 96768, while the sum is 46.

The square root of 1187038981 is about 34453.4320641645. The cubic root of 1187038981 is about 1058.8188400696.

The spelling of 1187038981 in words is "one billion, one hundred eighty-seven million, thirty-eight thousand, nine hundred eighty-one".