213166021 has 4 divisors (see below), whose sum is σ = 214473952. Its totient is φ = 211858092.

The previous prime is 213166003. The next prime is 213166027. The reversal of 213166021 is 120661312.

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 213166021 - 2⁵ = 213165989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213165983 and 213166001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213166027) 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, 653721 + ... + 654046.

It is an arithmetic number, because the mean of its divisors is an integer number (53618488).

Almost surely, 2^213166021 is an apocalyptic number.

It is an amenable number.

213166021 is a deficient number, since it is larger than the sum of its proper divisors (1307931).

213166021 is a wasteful number, since it uses less digits than its factorization.

213166021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1307930.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 213166021 is about 14600.2061971741. The cubic root of 213166021 is about 597.3643848773.

The spelling of 213166021 in words is "two hundred thirteen million, one hundred sixty-six thousand, twenty-one".