1961487987 has 4 divisors (see below), whose sum is σ = 2615317320. Its totient is φ = 1307658656.

The previous prime is 1961487977. The next prime is 1961488003. The reversal of 1961487987 is 7897841691.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1961487987 - 2⁶ = 1961487923 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1961487987.

It is not an unprimeable number, because it can be changed into a prime (1961487917) 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, 326914662 + ... + 326914667.

It is an arithmetic number, because the mean of its divisors is an integer number (653829330).

Almost surely, 2^1961487987 is an apocalyptic number.

1961487987 is a deficient number, since it is larger than the sum of its proper divisors (653829333).

1961487987 is an equidigital number, since it uses as much as digits as its factorization.

1961487987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 653829332.

The product of its digits is 6096384, while the sum is 60.

The square root of 1961487987 is about 44288.6891542299. The cubic root of 1961487987 is about 1251.7815635122.

The spelling of 1961487987 in words is "one billion, nine hundred sixty-one million, four hundred eighty-seven thousand, nine hundred eighty-seven".