213581421 has 16 divisors (see below), whose sum is σ = 335030400. Its totient is φ = 134011584.

The previous prime is 213581411. The next prime is 213581443. The reversal of 213581421 is 124185312.

It is not a de Polignac number, because 213581421 - 2¹⁵ = 213548653 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213581411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 232201 + ... + 233118.

It is an arithmetic number, because the mean of its divisors is an integer number (20939400).

Almost surely, 2^213581421 is an apocalyptic number.

It is an amenable number.

213581421 is a deficient number, since it is larger than the sum of its proper divisors (121448979).

213581421 is a wasteful number, since it uses less digits than its factorization.

213581421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 465345 (or 465339 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 213581421 is about 14614.4250998799. The cubic root of 213581421 is about 597.7521642405.

The spelling of 213581421 in words is "two hundred thirteen million, five hundred eighty-one thousand, four hundred twenty-one".