21160211731 has 4 divisors (see below), whose sum is σ = 21211948600. Its totient is φ = 21108474864.

The previous prime is 21160211711. The next prime is 21160211749. The reversal of 21160211731 is 13711206112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21160211731 - 2³¹ = 19012728083 is a prime.

It is a super-2 number, since 2×21160211731² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21160211696 and 21160211705.

It is not an unprimeable number, because it can be changed into a prime (21160211701) 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, 25867821 + ... + 25868638.

It is an arithmetic number, because the mean of its divisors is an integer number (5302987150).

Almost surely, 2^21160211731 is an apocalyptic number.

21160211731 is a deficient number, since it is larger than the sum of its proper divisors (51736869).

21160211731 is an equidigital number, since it uses as much as digits as its factorization.

21160211731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51736868.

The product of its (nonzero) digits is 504, while the sum is 25.

Adding to 21160211731 its reverse (13711206112), we get a palindrome (34871417843).

The spelling of 21160211731 in words is "twenty-one billion, one hundred sixty million, two hundred eleven thousand, seven hundred thirty-one".