20421452514555 has 24 divisors (see below), whose sum is σ = 35510274428928. Its totient is φ = 10856644396416.

The previous prime is 20421452514521. The next prime is 20421452514581. The reversal of 20421452514555 is 55541525412402.

20421452514555 is a `hidden beast` number, since 2 + 0 + 4 + 2 + 1 + 45 + 2 + 51 + 4 + 555 = 666.

It is not a de Polignac number, because 20421452514555 - 2¹⁰ = 20421452513531 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 20421452514555.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 724922107 + ... + 724950276.

It is an arithmetic number, because the mean of its divisors is an integer number (1479594767872).

Almost surely, 2^{20421452514555} is an apocalyptic number.

20421452514555 is a deficient number, since it is larger than the sum of its proper divisors (15088821914373).

20421452514555 is a wasteful number, since it uses less digits than its factorization.

20421452514555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1449872707 (or 1449872704 counting only the distinct ones).

The product of its (nonzero) digits is 1600000, while the sum is 45.

Adding to 20421452514555 its reverse (55541525412402), we get a palindrome (75962977926957).

The spelling of 20421452514555 in words is "twenty trillion, four hundred twenty-one billion, four hundred fifty-two million, five hundred fourteen thousand, five hundred fifty-five".