21549071 has 2 divisors, whose sum is σ = 21549072. Its totient is φ = 21549070.

The previous prime is 21549049. The next prime is 21549079. The reversal of 21549071 is 17094512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21549071 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21549079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10774535 + 10774536.

It is an arithmetic number, because the mean of its divisors is an integer number (10774536).

Almost surely, 2^21549071 is an apocalyptic number.

21549071 is a deficient number, since it is larger than the sum of its proper divisors (1).

21549071 is an equidigital number, since it uses as much as digits as its factorization.

21549071 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 21549071 is about 4642.0976939311. The cubic root of 21549071 is about 278.2762767656.

The spelling of 21549071 in words is "twenty-one million, five hundred forty-nine thousand, seventy-one".