1641278687 has 4 divisors (see below), whose sum is σ = 1644429456. Its totient is φ = 1638127920.

The previous prime is 1641278677. The next prime is 1641278701. The reversal of 1641278687 is 7868721461.

It is a happy number.

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 1641278687 - 2¹⁰ = 1641277663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1641278677) 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, 1574603 + ... + 1575644.

It is an arithmetic number, because the mean of its divisors is an integer number (411107364).

Almost surely, 2^1641278687 is an apocalyptic number.

1641278687 is a deficient number, since it is larger than the sum of its proper divisors (3150769).

1641278687 is an equidigital number, since it uses as much as digits as its factorization.

1641278687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3150768.

The product of its digits is 903168, while the sum is 50.

The square root of 1641278687 is about 40512.6978489461. The cubic root of 1641278687 is about 1179.5801165768.

The spelling of 1641278687 in words is "one billion, six hundred forty-one million, two hundred seventy-eight thousand, six hundred eighty-seven".