21054536 has 8 divisors (see below), whose sum is σ = 39477270. Its totient is φ = 10527264.

The previous prime is 21054533. The next prime is 21054541. The reversal of 21054536 is 63545012.

It can be written as a sum of positive squares in only one way, i.e., 16240900 + 4813636 = 4030^2 + 2194^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21054533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1315901 + ... + 1315916.

Almost surely, 2^21054536 is an apocalyptic number.

It is an amenable number.

21054536 is a deficient number, since it is larger than the sum of its proper divisors (18422734).

21054536 is a wasteful number, since it uses less digits than its factorization.

21054536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2631823 (or 2631819 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 21054536 is about 4588.5222021910. The cubic root of 21054536 is about 276.1310376858.

Adding to 21054536 its reverse (63545012), we get a palindrome (84599548).

The spelling of 21054536 in words is "twenty-one million, fifty-four thousand, five hundred thirty-six".