21505053340356 has 48 divisors (see below), whose sum is σ = 54844007016960. Its totient is φ = 6529048450560.

The previous prime is 21505053340327. The next prime is 21505053340399. The reversal of 21505053340356 is 65304335050512.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1700266711 + ... + 1700279358.

It is an arithmetic number, because the mean of its divisors is an integer number (1142583479520).

Almost surely, 2^{21505053340356} is an apocalyptic number.

It is an amenable number.

21505053340356 is an abundant number, since it is smaller than the sum of its proper divisors (33338953676604).

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

21505053340356 is a wasteful number, since it uses less digits than its factorization.

21505053340356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3400546124 (or 3400546122 counting only the distinct ones).

The product of its (nonzero) digits is 810000, while the sum is 42.

Adding to 21505053340356 its reverse (65304335050512), we get a palindrome (86809388390868).

The spelling of 21505053340356 in words is "twenty-one trillion, five hundred five billion, fifty-three million, three hundred forty thousand, three hundred fifty-six".