21010262656 has 16 divisors (see below), whose sum is σ = 41856382890. Its totient is φ = 10505131264.

The previous prime is 21010262599. The next prime is 21010262659. The reversal of 21010262656 is 65626201012.

It can be written as a sum of positive squares in only one way, i.e., 20678440000 + 331822656 = 143800^2 + 18216^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a super-2 number, since 2×21010262656² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21010262659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82071211 + ... + 82071466.

Almost surely, 2^21010262656 is an apocalyptic number.

It is an amenable number.

21010262656 is a deficient number, since it is larger than the sum of its proper divisors (20846120234).

21010262656 is an equidigital number, since it uses as much as digits as its factorization.

21010262656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164142691 (or 164142679 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

Adding to 21010262656 its reverse (65626201012), we get a palindrome (86636463668).

The spelling of 21010262656 in words is "twenty-one billion, ten million, two hundred sixty-two thousand, six hundred fifty-six".