212164021 has 4 divisors (see below), whose sum is σ = 217098112. Its totient is φ = 207229932.

The previous prime is 212163989. The next prime is 212164027. The reversal of 212164021 is 120461212.

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 212164021 - 2⁵ = 212163989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 212164021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212164027) 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, 2466981 + ... + 2467066.

It is an arithmetic number, because the mean of its divisors is an integer number (54274528).

Almost surely, 2^212164021 is an apocalyptic number.

It is an amenable number.

212164021 is a deficient number, since it is larger than the sum of its proper divisors (4934091).

212164021 is an equidigital number, since it uses as much as digits as its factorization.

212164021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4934090.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 212164021 is about 14565.8511938026. The cubic root of 212164021 is about 596.4269318030.

The spelling of 212164021 in words is "two hundred twelve million, one hundred sixty-four thousand, twenty-one".