20751165109 has 4 divisors (see below), whose sum is σ = 20760586816. Its totient is φ = 20741743404.

The previous prime is 20751165103. The next prime is 20751165121. The reversal of 20751165109 is 90156115702.

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: 90156115702 = 2 ⋅45078057851.

It is a cyclic number.

It is not a de Polignac number, because 20751165109 - 2¹³ = 20751156917 is a prime.

It is a super-2 number, since 2×20751165109² (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 (20751165103) 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, 4707549 + ... + 4711954.

It is an arithmetic number, because the mean of its divisors is an integer number (5190146704).

Almost surely, 2^20751165109 is an apocalyptic number.

It is an amenable number.

20751165109 is a deficient number, since it is larger than the sum of its proper divisors (9421707).

20751165109 is an equidigital number, since it uses as much as digits as its factorization.

20751165109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9421706.

The product of its (nonzero) digits is 18900, while the sum is 37.

The spelling of 20751165109 in words is "twenty billion, seven hundred fifty-one million, one hundred sixty-five thousand, one hundred nine".