20423251510555 has 16 divisors (see below), whose sum is σ = 26032982174784. Its totient is φ = 15328061639680.

The previous prime is 20423251510553. The next prime is 20423251510583. The reversal of 20423251510555 is 55501515232402.

It is not a de Polignac number, because 20423251510555 - 2¹ = 20423251510553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20423251510553) 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, 386265442 + ... + 386318311.

It is an arithmetic number, because the mean of its divisors is an integer number (1627061385924).

Almost surely, 2^{20423251510555} is an apocalyptic number.

20423251510555 is a deficient number, since it is larger than the sum of its proper divisors (5609730664229).

20423251510555 is a wasteful number, since it uses less digits than its factorization.

20423251510555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 772584086.

The product of its (nonzero) digits is 300000, while the sum is 40.

Adding to 20423251510555 its reverse (55501515232402), we get a palindrome (75924766742957).

The spelling of 20423251510555 in words is "twenty trillion, four hundred twenty-three billion, two hundred fifty-one million, five hundred ten thousand, five hundred fifty-five".