210013981 has 4 divisors (see below), whose sum is σ = 213573600. Its totient is φ = 206454364.

The previous prime is 210013967. The next prime is 210014059. The reversal of 210013981 is 189310012.

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 210013981 - 2²³ = 201625373 is a prime.

It is a super-2 number, since 2×210013981² = 88211744430936722, 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 (210013081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1779721 + ... + 1779838.

It is an arithmetic number, because the mean of its divisors is an integer number (53393400).

Almost surely, 2^210013981 is an apocalyptic number.

It is an amenable number.

210013981 is a deficient number, since it is larger than the sum of its proper divisors (3559619).

210013981 is an equidigital number, since it uses as much as digits as its factorization.

210013981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3559618.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 210013981 is about 14491.8591284900. The cubic root of 210013981 is about 594.4053857729.

Adding to 210013981 its reverse (189310012), we get a palindrome (399323993).

The spelling of 210013981 in words is "two hundred ten million, thirteen thousand, nine hundred eighty-one".