21106437 has 8 divisors (see below), whose sum is σ = 30700320. Its totient is φ = 12791760.

The previous prime is 21106429. The next prime is 21106441. The reversal of 21106437 is 73460112.

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

It is not a de Polignac number, because 21106437 - 2³ = 21106429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21106447) 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, 319762 + ... + 319827.

It is an arithmetic number, because the mean of its divisors is an integer number (3837540).

Almost surely, 2^21106437 is an apocalyptic number.

It is an amenable number.

21106437 is a deficient number, since it is larger than the sum of its proper divisors (9593883).

21106437 is a wasteful number, since it uses less digits than its factorization.

21106437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639603.

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 21106437 is about 4594.1742457160. The cubic root of 21106437 is about 276.3577460308.

Adding to 21106437 its reverse (73460112), we get a palindrome (94566549).

The spelling of 21106437 in words is "twenty-one million, one hundred six thousand, four hundred thirty-seven".