20011601557 has 4 divisors (see below), whose sum is σ = 20019945600. Its totient is φ = 20003257516.

The previous prime is 20011601551. The next prime is 20011601567. The reversal of 20011601557 is 75510611002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 75510611002 = 2 ⋅37755305501.

It is a cyclic number.

It is not a de Polignac number, because 20011601557 - 2²⁷ = 19877383829 is a prime.

It is a super-2 number, since 2×20011601557² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20011601551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4168423 + ... + 4173220.

It is an arithmetic number, because the mean of its divisors is an integer number (5004986400).

Almost surely, 2^20011601557 is an apocalyptic number.

It is an amenable number.

20011601557 is a deficient number, since it is larger than the sum of its proper divisors (8344043).

20011601557 is an equidigital number, since it uses as much as digits as its factorization.

20011601557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8344042.

The product of its (nonzero) digits is 2100, while the sum is 28.

The spelling of 20011601557 in words is "twenty billion, eleven million, six hundred one thousand, five hundred fifty-seven".