21445156 has 6 divisors (see below), whose sum is σ = 37529030. Its totient is φ = 10722576.

The previous prime is 21445147. The next prime is 21445157. The reversal of 21445156 is 65154412.

It can be written as a sum of positive squares in only one way, i.e., 21160000 + 285156 = 4600^2 + 534^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21445157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2680641 + ... + 2680648.

Almost surely, 2^21445156 is an apocalyptic number.

It is an amenable number.

21445156 is a deficient number, since it is larger than the sum of its proper divisors (16083874).

21445156 is a wasteful number, since it uses less digits than its factorization.

21445156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5361293 (or 5361291 counting only the distinct ones).

The product of its digits is 4800, while the sum is 28.

The square root of 21445156 is about 4630.8914908471. The cubic root of 21445156 is about 277.8282499339.

Adding to 21445156 its reverse (65154412), we get a palindrome (86599568).

The spelling of 21445156 in words is "twenty-one million, four hundred forty-five thousand, one hundred fifty-six".