20551661111157 has 16 divisors (see below), whose sum is σ = 29987625978432. Its totient is φ = 12416260219520.

The previous prime is 20551661111143. The next prime is 20551661111173. The reversal of 20551661111157 is 75111116615502.

It is a cyclic number.

It is not a de Polignac number, because 20551661111157 - 2¹⁶ = 20551661045621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20551661111117) 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, 982288608 + ... + 982309529.

It is an arithmetic number, because the mean of its divisors is an integer number (1874226623652).

Almost surely, 2^{20551661111157} is an apocalyptic number.

It is an amenable number.

20551661111157 is a deficient number, since it is larger than the sum of its proper divisors (9435964867275).

20551661111157 is a wasteful number, since it uses less digits than its factorization.

20551661111157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1964598468.

The product of its (nonzero) digits is 63000, while the sum is 42.

Adding to 20551661111157 its reverse (75111116615502), we get a palindrome (95662777726659).

The spelling of 20551661111157 in words is "twenty trillion, five hundred fifty-one billion, six hundred sixty-one million, one hundred eleven thousand, one hundred fifty-seven".