21144499 has 4 divisors (see below), whose sum is σ = 21399336. Its totient is φ = 20889664.

The previous prime is 21144469. The next prime is 21144547. The reversal of 21144499 is 99444112.

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 21144499 - 2⁵ = 21144467 is a prime.

It is a super-2 number, since 2×21144499² = 894179675922002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21144419) 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, 127294 + ... + 127459.

It is an arithmetic number, because the mean of its divisors is an integer number (5349834).

Almost surely, 2^21144499 is an apocalyptic number.

21144499 is a deficient number, since it is larger than the sum of its proper divisors (254837).

21144499 is an equidigital number, since it uses as much as digits as its factorization.

21144499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254836.

The product of its digits is 10368, while the sum is 34.

The square root of 21144499 is about 4598.3148000110. The cubic root of 21144499 is about 276.5237682404.

The spelling of 21144499 in words is "twenty-one million, one hundred forty-four thousand, four hundred ninety-nine".