21099437 has 8 divisors (see below), whose sum is σ = 21987072. Its totient is φ = 20224800.

The previous prime is 21099427. The next prime is 21099451. The reversal of 21099437 is 73499012.

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

It is a cyclic number.

It is not a de Polignac number, because 21099437 - 2²⁴ = 4322221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21099397 and 21099406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21099427) 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, 137 + ... + 6497.

It is an arithmetic number, because the mean of its divisors is an integer number (2748384).

Almost surely, 2^21099437 is an apocalyptic number.

It is an amenable number.

21099437 is a deficient number, since it is larger than the sum of its proper divisors (887635).

21099437 is a wasteful number, since it uses less digits than its factorization.

21099437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6499.

The product of its (nonzero) digits is 13608, while the sum is 35.

The square root of 21099437 is about 4593.4123481351. The cubic root of 21099437 is about 276.3271910849.

The spelling of 21099437 in words is "twenty-one million, ninety-nine thousand, four hundred thirty-seven".