3187445891621 has 4 divisors (see below), whose sum is σ = 3187457864652. Its totient is φ = 3187433918592.

The previous prime is 3187445891611. The next prime is 3187445891659. The reversal of 3187445891621 is 1261985447813.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 994884558721 + 2192561332900 = 997439^2 + 1480730^2 .

It is a cyclic number.

It is not a de Polignac number, because 3187445891621 - 2²² = 3187441697317 is a prime.

It is a super-2 number, since 2×3187445891621² (a number of 26 digits) 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 (3187445891611) 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, 5577890 + ... + 6122723.

It is an arithmetic number, because the mean of its divisors is an integer number (796864466163).

Almost surely, 2^{3187445891621} is an apocalyptic number.

It is an amenable number.

3187445891621 is a deficient number, since it is larger than the sum of its proper divisors (11973031).

3187445891621 is a wasteful number, since it uses less digits than its factorization.

3187445891621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11973030.

The product of its digits is 11612160, while the sum is 59.

The spelling of 3187445891621 in words is "three trillion, one hundred eighty-seven billion, four hundred forty-five million, eight hundred ninety-one thousand, six hundred twenty-one".