21349031 has 4 divisors (see below), whose sum is σ = 23289864. Its totient is φ = 19408200.

The previous prime is 21349019. The next prime is 21349033. The reversal of 21349031 is 13094312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21349031 - 2¹⁰ = 21348007 is a prime.

It is a super-2 number, since 2×21349031² = 911562249277922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21348988 and 21349006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21349033) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 970400 + ... + 970421.

It is an arithmetic number, because the mean of its divisors is an integer number (5822466).

Almost surely, 2^21349031 is an apocalyptic number.

21349031 is a deficient number, since it is larger than the sum of its proper divisors (1940833).

21349031 is a wasteful number, since it uses less digits than its factorization.

21349031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1940832.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 21349031 is about 4620.5011632939. The cubic root of 21349031 is about 277.4125190255.

The spelling of 21349031 in words is "twenty-one million, three hundred forty-nine thousand, thirty-one".