21054556 has 6 divisors (see below), whose sum is σ = 36845480. Its totient is φ = 10527276.

The previous prime is 21054541. The next prime is 21054559. The reversal of 21054556 is 65545012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21054559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2631816 + ... + 2631823.

Almost surely, 2^21054556 is an apocalyptic number.

It is an amenable number.

21054556 is a deficient number, since it is larger than the sum of its proper divisors (15790924).

21054556 is a wasteful number, since it uses less digits than its factorization.

21054556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5263643 (or 5263641 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 28.

The square root of 21054556 is about 4588.5243815414. The cubic root of 21054556 is about 276.1311251194.

Adding to 21054556 its reverse (65545012), we get a palindrome (86599568).

The spelling of 21054556 in words is "twenty-one million, fifty-four thousand, five hundred fifty-six".