21449399 has 4 divisors (see below), whose sum is σ = 21591600. Its totient is φ = 21307200.

The previous prime is 21449387. The next prime is 21449413. The reversal of 21449399 is 99394412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21449399 - 2⁸ = 21449143 is a prime.

It is a super-2 number, since 2×21449399² = 920153434922402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21449599) 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, 70874 + ... + 71175.

It is an arithmetic number, because the mean of its divisors is an integer number (5397900).

Almost surely, 2^21449399 is an apocalyptic number.

21449399 is a deficient number, since it is larger than the sum of its proper divisors (142201).

21449399 is a wasteful number, since it uses less digits than its factorization.

21449399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142200.

The product of its digits is 69984, while the sum is 41.

The square root of 21449399 is about 4631.3495873233. The cubic root of 21449399 is about 277.8465718263.

The spelling of 21449399 in words is "twenty-one million, four hundred forty-nine thousand, three hundred ninety-nine".