21552061 has 12 divisors (see below), whose sum is σ = 22933152. Its totient is φ = 20250504.

The previous prime is 21552059. The next prime is 21552067. The reversal of 21552061 is 16025512.

21552061 = 41² + 42² + ... + 401².

It is not a de Polignac number, because 21552061 - 2¹ = 21552059 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21552067) 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, 81816 + ... + 82078.

It is an arithmetic number, because the mean of its divisors is an integer number (1911096).

Almost surely, 2^21552061 is an apocalyptic number.

It is an amenable number.

21552061 is a deficient number, since it is larger than the sum of its proper divisors (1381091).

21552061 is a wasteful number, since it uses less digits than its factorization.

21552061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528 (or 509 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 21552061 is about 4642.4197354397. The cubic root of 21552061 is about 278.2891467340.

Adding to 21552061 its reverse (16025512), we get a palindrome (37577573).

The spelling of 21552061 in words is "twenty-one million, five hundred fifty-two thousand, sixty-one".