217103402155421 has 4 divisors (see below), whose sum is σ = 218812877763072. Its totient is φ = 215393926547772.

The previous prime is 217103402155333. The next prime is 217103402155429. The reversal of 217103402155421 is 124551204301712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 217103402155421 - 2³⁴ = 217086222286237 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217103402155429) 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, 854737803635 + ... + 854737803888.

It is an arithmetic number, because the mean of its divisors is an integer number (54703219440768).

Almost surely, 2^{217103402155421} is an apocalyptic number.

It is an amenable number.

217103402155421 is a deficient number, since it is larger than the sum of its proper divisors (1709475607651).

217103402155421 is a wasteful number, since it uses less digits than its factorization.

217103402155421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1709475607650.

The product of its (nonzero) digits is 67200, while the sum is 38.

The spelling of 217103402155421 in words is "two hundred seventeen trillion, one hundred three billion, four hundred two million, one hundred fifty-five thousand, four hundred twenty-one".