21272489 has 4 divisors (see below), whose sum is σ = 24311424. Its totient is φ = 18233556.

The previous prime is 21272483. The next prime is 21272507. The reversal of 21272489 is 98427212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21272489 - 2⁴ = 21272473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21272483) 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, 1519457 + ... + 1519470.

It is an arithmetic number, because the mean of its divisors is an integer number (6077856).

Almost surely, 2^21272489 is an apocalyptic number.

It is an amenable number.

21272489 is a deficient number, since it is larger than the sum of its proper divisors (3038935).

21272489 is an equidigital number, since it uses as much as digits as its factorization.

21272489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3038934.

The product of its digits is 16128, while the sum is 35.

The square root of 21272489 is about 4612.2108581460. The cubic root of 21272489 is about 277.0805892706.

The spelling of 21272489 in words is "twenty-one million, two hundred seventy-two thousand, four hundred eighty-nine".