21437013 has 8 divisors (see below), whose sum is σ = 30781408. Its totient is φ = 13191984.

The previous prime is 21437011. The next prime is 21437021. The reversal of 21437013 is 31073412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21437013 - 2¹ = 21437011 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21437011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274795 + ... + 274872.

It is an arithmetic number, because the mean of its divisors is an integer number (3847676).

Almost surely, 2^21437013 is an apocalyptic number.

It is an amenable number.

21437013 is a deficient number, since it is larger than the sum of its proper divisors (9344395).

21437013 is a wasteful number, since it uses less digits than its factorization.

21437013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549683.

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 21437013 is about 4630.0122030077. The cubic root of 21437013 is about 277.7930805021.

The spelling of 21437013 in words is "twenty-one million, four hundred thirty-seven thousand, thirteen".