212121806 has 8 divisors (see below), whose sum is σ = 342658344. Its totient is φ = 97902360.

The previous prime is 212121781. The next prime is 212121817. The reversal of 212121806 is 608121212.

212121806 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4079240 + ... + 4079291.

It is an arithmetic number, because the mean of its divisors is an integer number (42832293).

Almost surely, 2^212121806 is an apocalyptic number.

212121806 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

212121806 is a deficient number, since it is larger than the sum of its proper divisors (130536538).

212121806 is a wasteful number, since it uses less digits than its factorization.

212121806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8158546.

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 212121806 is about 14564.4020131278. The cubic root of 212121806 is about 596.3873714778.

The spelling of 212121806 in words is "two hundred twelve million, one hundred twenty-one thousand, eight hundred six".