2166221655257 has 4 divisors (see below), whose sum is σ = 2363150896656. Its totient is φ = 1969292413860.

The previous prime is 2166221655211. The next prime is 2166221655337. The reversal of 2166221655257 is 7525561226612.

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 2166221655257 - 2⁸ = 2166221655001 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2166221655457) 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, 98464620683 + ... + 98464620704.

It is an arithmetic number, because the mean of its divisors is an integer number (590787724164).

Almost surely, 2^{2166221655257} is an apocalyptic number.

It is an amenable number.

2166221655257 is a deficient number, since it is larger than the sum of its proper divisors (196929241399).

2166221655257 is a wasteful number, since it uses less digits than its factorization.

2166221655257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196929241398.

The product of its digits is 3024000, while the sum is 50.

The spelling of 2166221655257 in words is "two trillion, one hundred sixty-six billion, two hundred twenty-one million, six hundred fifty-five thousand, two hundred fifty-seven".