21549079 has 2 divisors, whose sum is σ = 21549080. Its totient is φ = 21549078.

The previous prime is 21549071. The next prime is 21549083. The reversal of 21549079 is 97094512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21549079 - 2³ = 21549071 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21549071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10774539 + 10774540.

It is an arithmetic number, because the mean of its divisors is an integer number (10774540).

Almost surely, 2^21549079 is an apocalyptic number.

21549079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21549079 is an equidigital number, since it uses as much as digits as its factorization.

21549079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 21549079 is about 4642.0985556104. The cubic root of 21549079 is about 278.2763112019.

It can be divided in two parts, 215 and 49079, that added together give a palindrome (49294).

The spelling of 21549079 in words is "twenty-one million, five hundred forty-nine thousand, seventy-nine".