217131400643 has 4 divisors (see below), whose sum is σ = 217132895760. Its totient is φ = 217129905528.

The previous prime is 217131400597. The next prime is 217131400667. The reversal of 217131400643 is 346004131712.

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 217131400643 - 2¹⁶ = 217131335107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217131402643) 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, 503063 + ... + 829056.

It is an arithmetic number, because the mean of its divisors is an integer number (54283223940).

Almost surely, 2^217131400643 is an apocalyptic number.

217131400643 is a deficient number, since it is larger than the sum of its proper divisors (1495117).

217131400643 is a wasteful number, since it uses less digits than its factorization.

217131400643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1495116.

The product of its (nonzero) digits is 12096, while the sum is 32.

The spelling of 217131400643 in words is "two hundred seventeen billion, one hundred thirty-one million, four hundred thousand, six hundred forty-three".