643136387461 has 32 divisors (see below), whose sum is σ = 677311303680. Its totient is φ = 609892416000.

The previous prime is 643136387437. The next prime is 643136387479. The reversal of 643136387461 is 164783631346.

It is a 6-Lehmer number, since φ(643136387461) divides (643136387461-1)⁶.

It is a cyclic number.

It is not a de Polignac number, because 643136387461 - 2¹⁹ = 643135863173 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643136387399 and 643136387408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643136307461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 153089161 + ... + 153093361.

It is an arithmetic number, because the mean of its divisors is an integer number (21165978240).

Almost surely, 2^643136387461 is an apocalyptic number.

643136387461 is the 428665-th centered heptagonal number.

It is an amenable number.

643136387461 is a deficient number, since it is larger than the sum of its proper divisors (34174916219).

643136387461 is a wasteful number, since it uses less digits than its factorization.

643136387461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4765.

The product of its digits is 5225472, while the sum is 52.

The spelling of 643136387461 in words is "six hundred forty-three billion, one hundred thirty-six million, three hundred eighty-seven thousand, four hundred sixty-one".