21034437 has 4 divisors (see below), whose sum is σ = 28045920. Its totient is φ = 14022956.

The previous prime is 21034421. The next prime is 21034471. The reversal of 21034437 is 73443012.

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 21034437 - 2⁴ = 21034421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21034417) 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, 3505737 + ... + 3505742.

It is an arithmetic number, because the mean of its divisors is an integer number (7011480).

Almost surely, 2^21034437 is an apocalyptic number.

It is an amenable number.

21034437 is a deficient number, since it is larger than the sum of its proper divisors (7011483).

21034437 is an equidigital number, since it uses as much as digits as its factorization.

21034437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7011482.

The product of its (nonzero) digits is 2016, while the sum is 24.

The square root of 21034437 is about 4586.3315405670. The cubic root of 21034437 is about 276.0431433292.

Adding to 21034437 its reverse (73443012), we get a palindrome (94477449).

The spelling of 21034437 in words is "twenty-one million, thirty-four thousand, four hundred thirty-seven".