21405341652250 has 64 divisors (see below), whose sum is σ = 43009110237600. Its totient is φ = 7948091289600.

The previous prime is 21405341652193. The next prime is 21405341652269. The reversal of 21405341652250 is 5225614350412.

It can be written as a sum of positive squares in 16 ways, for example, as 1516890287641 + 19888451364609 = 1231621^2 + 4459647^2 .

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 34186675 + ... + 34807174.

Almost surely, 2^{21405341652250} is an apocalyptic number.

21405341652250 is an abundant number, since it is smaller than the sum of its proper divisors (21603768585350).

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

21405341652250 is a wasteful number, since it uses less digits than its factorization.

21405341652250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68993956 (or 68993946 counting only the distinct ones).

The product of its (nonzero) digits is 288000, while the sum is 40.

The spelling of 21405341652250 in words is "twenty-one trillion, four hundred five billion, three hundred forty-one million, six hundred fifty-two thousand, two hundred fifty".