21031553105 has 16 divisors (see below), whose sum is σ = 25300069200. Its totient is φ = 16783828992.

The previous prime is 21031553071. The next prime is 21031553113. The reversal of 21031553105 is 50135513012.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 3148107664 + 17883445441 = 56108^2 + 133729^2 .

It is a cyclic number.

It is not a de Polignac number, because 21031553105 - 2¹² = 21031549009 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3967817 + ... + 3973113.

It is an arithmetic number, because the mean of its divisors is an integer number (1581254325).

Almost surely, 2^21031553105 is an apocalyptic number.

It is an amenable number.

21031553105 is a deficient number, since it is larger than the sum of its proper divisors (4268516095).

21031553105 is a wasteful number, since it uses less digits than its factorization.

21031553105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7108.

The product of its (nonzero) digits is 2250, while the sum is 26.

The spelling of 21031553105 in words is "twenty-one billion, thirty-one million, five hundred fifty-three thousand, one hundred five".