20920899761 has 4 divisors (see below), whose sum is σ = 20921252352. Its totient is φ = 20920547172.

The previous prime is 20920899757. The next prime is 20920899767. The reversal of 20920899761 is 16799802902.

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: 16799802902 = 2 ⋅8399901451.

It is a cyclic number.

It is not a de Polignac number, because 20920899761 - 2² = 20920899757 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20920899767) 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, 63041 + ... + 214046.

It is an arithmetic number, because the mean of its divisors is an integer number (5230313088).

Almost surely, 2^20920899761 is an apocalyptic number.

It is an amenable number.

20920899761 is a deficient number, since it is larger than the sum of its proper divisors (352591).

20920899761 is an equidigital number, since it uses as much as digits as its factorization.

20920899761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352590.

The product of its (nonzero) digits is 979776, while the sum is 53.

The spelling of 20920899761 in words is "twenty billion, nine hundred twenty million, eight hundred ninety-nine thousand, seven hundred sixty-one".