21020513145455 has 16 divisors (see below), whose sum is σ = 25645538800704. Its totient is φ = 16535954407680.

The previous prime is 21020513145449. The next prime is 21020513145487. The reversal of 21020513145455 is 55454131502012.

It is not a de Polignac number, because 21020513145455 - 2⁴⁴ = 3428327101039 is a prime.

It is a congruent number.

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, 8894654 + ... + 11007083.

It is an arithmetic number, because the mean of its divisors is an integer number (1602846175044).

Almost surely, 2^{21020513145455} is an apocalyptic number.

21020513145455 is a deficient number, since it is larger than the sum of its proper divisors (4625025655249).

21020513145455 is a wasteful number, since it uses less digits than its factorization.

21020513145455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19905266.

The product of its (nonzero) digits is 120000, while the sum is 38.

Adding to 21020513145455 its reverse (55454131502012), we get a palindrome (76474644647467).

The spelling of 21020513145455 in words is "twenty-one trillion, twenty billion, five hundred thirteen million, one hundred forty-five thousand, four hundred fifty-five".