21356225765436 has 48 divisors (see below), whose sum is σ = 50391409267584. Its totient is φ = 7039154477376.

The previous prime is 21356225765431. The next prime is 21356225765449. The reversal of 21356225765436 is 63456752265312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21356225765431) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27326130 + ... + 28096793.

It is an arithmetic number, because the mean of its divisors is an integer number (1049821026408).

Almost surely, 2^{21356225765436} is an apocalyptic number.

It is an amenable number.

21356225765436 is an abundant number, since it is smaller than the sum of its proper divisors (29035183502148).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21356225765436 is a wasteful number, since it uses less digits than its factorization.

21356225765436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55423290 (or 55423288 counting only the distinct ones).

The product of its digits is 54432000, while the sum is 57.

The spelling of 21356225765436 in words is "twenty-one trillion, three hundred fifty-six billion, two hundred twenty-five million, seven hundred sixty-five thousand, four hundred thirty-six".