21550053 has 24 divisors (see below), whose sum is σ = 34510080. Its totient is φ = 11914560.

The previous prime is 21550049. The next prime is 21550069. The reversal of 21550053 is 35005512.

It is not a de Polignac number, because 21550053 - 2² = 21550049 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21550003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2193 + ... + 6921.

It is an arithmetic number, because the mean of its divisors is an integer number (1437920).

Almost surely, 2^21550053 is an apocalyptic number.

It is an amenable number.

21550053 is a deficient number, since it is larger than the sum of its proper divisors (12960027).

21550053 is a wasteful number, since it uses less digits than its factorization.

21550053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4777 (or 4770 counting only the distinct ones).

The product of its (nonzero) digits is 750, while the sum is 21.

The square root of 21550053 is about 4642.2034638736. The cubic root of 21550053 is about 278.2805037560.

Adding to 21550053 its reverse (35005512), we get a palindrome (56555565).

The spelling of 21550053 in words is "twenty-one million, five hundred fifty thousand, fifty-three".