21424131 has 24 divisors (see below), whose sum is σ = 33830784. Its totient is φ = 13006080.

The previous prime is 21424129. The next prime is 21424159. The reversal of 21424131 is 13142412.

It is not a de Polignac number, because 21424131 - 2¹ = 21424129 is a prime.

It is a super-2 number, since 2×21424131² = 917986778210322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21424171) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2485 + ... + 7001.

It is an arithmetic number, because the mean of its divisors is an integer number (1409616).

Almost surely, 2^21424131 is an apocalyptic number.

21424131 is a deficient number, since it is larger than the sum of its proper divisors (12406653).

21424131 is a wasteful number, since it uses less digits than its factorization.

21424131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4571 (or 4568 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 21424131 is about 4628.6208529107. The cubic root of 21424131 is about 277.7374252435.

Adding to 21424131 its reverse (13142412), we get a palindrome (34566543).

The spelling of 21424131 in words is "twenty-one million, four hundred twenty-four thousand, one hundred thirty-one".