20356651121 has 4 divisors (see below), whose sum is σ = 20740738932. Its totient is φ = 19972563312.

The previous prime is 20356651061. The next prime is 20356651153. The reversal of 20356651121 is 12115665302.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4947152896 + 15409498225 = 70336^2 + 124135^2 .

It is a cyclic number.

It is not a de Polignac number, because 20356651121 - 2¹⁸ = 20356388977 is a prime.

It is a super-2 number, since 2×20356651121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20356551121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 192043826 + ... + 192043931.

It is an arithmetic number, because the mean of its divisors is an integer number (5185184733).

Almost surely, 2^20356651121 is an apocalyptic number.

It is an amenable number.

20356651121 is a deficient number, since it is larger than the sum of its proper divisors (384087811).

20356651121 is an equidigital number, since it uses as much as digits as its factorization.

20356651121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384087810.

The product of its (nonzero) digits is 10800, while the sum is 32.

The spelling of 20356651121 in words is "twenty billion, three hundred fifty-six million, six hundred fifty-one thousand, one hundred twenty-one".