21553011 has 12 divisors (see below), whose sum is σ = 32770920. Its totient is φ = 13612320.

The previous prime is 21553009. The next prime is 21553039. The reversal of 21553011 is 11035512.

It is not a de Polignac number, because 21553011 - 2¹ = 21553009 is a prime.

It is a super-2 number, since 2×21553011² = 929064566332242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21553111) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 62850 + ... + 63191.

It is an arithmetic number, because the mean of its divisors is an integer number (2730910).

Almost surely, 2^21553011 is an apocalyptic number.

21553011 is a deficient number, since it is larger than the sum of its proper divisors (11217909).

21553011 is a wasteful number, since it uses less digits than its factorization.

21553011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126066 (or 126063 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 18.

The square root of 21553011 is about 4642.5220516439. The cubic root of 21553011 is about 278.2932356052.

Adding to 21553011 its reverse (11035512), we get a palindrome (32588523).

The spelling of 21553011 in words is "twenty-one million, five hundred fifty-three thousand, eleven".