21155361522250 has 16 divisors (see below), whose sum is σ = 39602836770120. Its totient is φ = 8462144608800.

The previous prime is 21155361522247. The next prime is 21155361522259. The reversal of 21155361522250 is 5222516355112.

It can be written as a sum of positive squares in 4 ways, for example, as 14101519529601 + 7053841992649 = 3755199^2 + 2655907^2 .

It is a super-2 number, since 2×21155361522250² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21155361522259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42310722795 + ... + 42310723294.

Almost surely, 2^{21155361522250} is an apocalyptic number.

21155361522250 is a deficient number, since it is larger than the sum of its proper divisors (18447475247870).

21155361522250 is an equidigital number, since it uses as much as digits as its factorization.

21155361522250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84621446106 (or 84621446096 counting only the distinct ones).

The product of its (nonzero) digits is 180000, while the sum is 40.

Adding to 21155361522250 its reverse (5222516355112), we get a palindrome (26377877877362).

The spelling of 21155361522250 in words is "twenty-one trillion, one hundred fifty-five billion, three hundred sixty-one million, five hundred twenty-two thousand, two hundred fifty".