21418499 has 4 divisors (see below), whose sum is σ = 21720240. Its totient is φ = 21116760.

The previous prime is 21418477. The next prime is 21418513. The reversal of 21418499 is 99481412.

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 21418499 - 2¹⁶ = 21352963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21418409) 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, 150764 + ... + 150905.

It is an arithmetic number, because the mean of its divisors is an integer number (5430060).

Almost surely, 2^21418499 is an apocalyptic number.

21418499 is a deficient number, since it is larger than the sum of its proper divisors (301741).

21418499 is an equidigital number, since it uses as much as digits as its factorization.

21418499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301740.

The product of its digits is 20736, while the sum is 38.

The square root of 21418499 is about 4628.0124243567. The cubic root of 21418499 is about 277.7130858002.

The spelling of 21418499 in words is "twenty-one million, four hundred eighteen thousand, four hundred ninety-nine".