21437423 has 8 divisors (see below), whose sum is σ = 24532992. Its totient is φ = 18350136.

The previous prime is 21437411. The next prime is 21437431. The reversal of 21437423 is 32473412.

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

It is not a de Polignac number, because 21437423 - 2⁴ = 21437407 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21437392 and 21437401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21437443) 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, 5186 + ... + 8352.

It is an arithmetic number, because the mean of its divisors is an integer number (3066624).

Almost surely, 2^21437423 is an apocalyptic number.

21437423 is a deficient number, since it is larger than the sum of its proper divisors (3095569).

21437423 is an equidigital number, since it uses as much as digits as its factorization.

21437423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4141.

The product of its digits is 4032, while the sum is 26.

The square root of 21437423 is about 4630.0564791372. The cubic root of 21437423 is about 277.7948514957.

The spelling of 21437423 in words is "twenty-one million, four hundred thirty-seven thousand, four hundred twenty-three".