211401309 has 16 divisors (see below), whose sum is σ = 322959488. Its totient is φ = 120491712.

The previous prime is 211401299. The next prime is 211401319. The reversal of 211401309 is 903104112.

It is an interprime number because it is at equal distance from previous prime (211401299) and next prime (211401319).

It is not a de Polignac number, because 211401309 - 2⁸ = 211401053 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211401319) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4342 + ... + 21015.

It is an arithmetic number, because the mean of its divisors is an integer number (20184968).

Almost surely, 2^211401309 is an apocalyptic number.

It is an amenable number.

211401309 is a deficient number, since it is larger than the sum of its proper divisors (111558179).

211401309 is a wasteful number, since it uses less digits than its factorization.

211401309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25764.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 211401309 is about 14539.6461098611. The cubic root of 211401309 is about 595.7113719283.

The spelling of 211401309 in words is "two hundred eleven million, four hundred one thousand, three hundred nine".