21431349 has 12 divisors (see below), whose sum is σ = 31015296. Its totient is φ = 14260392.

The previous prime is 21431341. The next prime is 21431353. The reversal of 21431349 is 94313412.

It is not a de Polignac number, because 21431349 - 2³ = 21431341 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431341) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3502 + ... + 7424.

It is an arithmetic number, because the mean of its divisors is an integer number (2584608).

Almost surely, 2^21431349 is an apocalyptic number.

It is an amenable number.

21431349 is a deficient number, since it is larger than the sum of its proper divisors (9583947).

21431349 is a wasteful number, since it uses less digits than its factorization.

21431349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4536 (or 4533 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 21431349 is about 4629.4005011448. The cubic root of 21431349 is about 277.7686125628.

The spelling of 21431349 in words is "twenty-one million, four hundred thirty-one thousand, three hundred forty-nine".