212508991 has 4 divisors (see below), whose sum is σ = 212854032. Its totient is φ = 212163952.

The previous prime is 212508971. The next prime is 212509007. The reversal of 212508991 is 199805212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 212508991 - 2²³ = 204120383 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 212508991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212508911) 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, 171595 + ... + 172828.

It is an arithmetic number, because the mean of its divisors is an integer number (53213508).

Almost surely, 2^212508991 is an apocalyptic number.

212508991 is a deficient number, since it is larger than the sum of its proper divisors (345041).

212508991 is an equidigital number, since it uses as much as digits as its factorization.

212508991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345040.

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 212508991 is about 14577.6881226071. The cubic root of 212508991 is about 596.7500120076.

The spelling of 212508991 in words is "two hundred twelve million, five hundred eight thousand, nine hundred ninety-one".