210688421 has 4 divisors (see below), whose sum is σ = 211981152. Its totient is φ = 209395692.

The previous prime is 210688417. The next prime is 210688427. The reversal of 210688421 is 124886012.

It is a happy number.

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 210688421 - 2² = 210688417 is a prime.

It is a super-2 number, since 2×210688421² = 88779221486946482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210688427) 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, 646121 + ... + 646446.

It is an arithmetic number, because the mean of its divisors is an integer number (52995288).

Almost surely, 2^210688421 is an apocalyptic number.

It is an amenable number.

210688421 is a deficient number, since it is larger than the sum of its proper divisors (1292731).

210688421 is a wasteful number, since it uses less digits than its factorization.

210688421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1292730.

The product of its (nonzero) digits is 6144, while the sum is 32.

The square root of 210688421 is about 14515.1100925897. The cubic root of 210688421 is about 595.0409980459.

The spelling of 210688421 in words is "two hundred ten million, six hundred eighty-eight thousand, four hundred twenty-one".