1964641687 has 4 divisors (see below), whose sum is σ = 1964961936. Its totient is φ = 1964321440.

The previous prime is 1964641619. The next prime is 1964641691. The reversal of 1964641687 is 7861464691.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1964641687 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 (1964641697) 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, 150739 + ... + 163252.

It is an arithmetic number, because the mean of its divisors is an integer number (491240484).

Almost surely, 2^1964641687 is an apocalyptic number.

1964641687 is a deficient number, since it is larger than the sum of its proper divisors (320249).

1964641687 is an equidigital number, since it uses as much as digits as its factorization.

1964641687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320248.

The product of its digits is 1741824, while the sum is 52.

The square root of 1964641687 is about 44324.2787532973. The cubic root of 1964641687 is about 1252.4520799246.

The spelling of 1964641687 in words is "one billion, nine hundred sixty-four million, six hundred forty-one thousand, six hundred eighty-seven".