21535533020425 has 24 divisors (see below), whose sum is σ = 28738410849432. Its totient is φ = 15949170048000.

The previous prime is 21535533020423. The next prime is 21535533020447. The reversal of 21535533020425 is 52402033553512.

It can be written as a sum of positive squares in 12 ways, for example, as 15786572525824 + 5748960494601 = 3973232^2 + 2397699^2 .

It is not a de Polignac number, because 21535533020425 - 2¹ = 21535533020423 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21535533020423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 415317046 + ... + 415368895.

It is an arithmetic number, because the mean of its divisors is an integer number (1197433785393).

Almost surely, 2^{21535533020425} is an apocalyptic number.

21535533020425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21535533020425 is a deficient number, since it is larger than the sum of its proper divisors (7202877829007).

21535533020425 is a wasteful number, since it uses less digits than its factorization.

21535533020425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830686029 (or 830686024 counting only the distinct ones).

The product of its (nonzero) digits is 540000, while the sum is 40.

Adding to 21535533020425 its reverse (52402033553512), we get a palindrome (73937566573937).

The spelling of 21535533020425 in words is "twenty-one trillion, five hundred thirty-five billion, five hundred thirty-three million, twenty thousand, four hundred twenty-five".