641215987 has 4 divisors (see below), whose sum is σ = 645519600. Its totient is φ = 636912376.

The previous prime is 641215969. The next prime is 641216041. The reversal of 641215987 is 789512146.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 789512146 = 2 ⋅394756073.

It is a cyclic number.

It is not a de Polignac number, because 641215987 - 2⁷ = 641215859 is a prime.

It is a super-2 number, since 2×641215987² = 822315883968768338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641215937) 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, 2151583 + ... + 2151880.

It is an arithmetic number, because the mean of its divisors is an integer number (161379900).

Almost surely, 2^641215987 is an apocalyptic number.

641215987 is a deficient number, since it is larger than the sum of its proper divisors (4303613).

641215987 is a wasteful number, since it uses less digits than its factorization.

641215987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4303612.

The product of its digits is 120960, while the sum is 43.

The square root of 641215987 is about 25322.2429298828. The cubic root of 641215987 is about 862.3193150040.

The spelling of 641215987 in words is "six hundred forty-one million, two hundred fifteen thousand, nine hundred eighty-seven".