20712781761 has 8 divisors (see below), whose sum is σ = 31562334144. Its totient is φ = 11835875280.

The previous prime is 20712781741. The next prime is 20712781763. The reversal of 20712781761 is 16718721702.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20712781761 - 2⁶ = 20712781697 is a prime.

It is a super-2 number, since 2×20712781761² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20712781763) 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 7 ways as a sum of consecutive naturals, for example, 493161450 + ... + 493161491.

It is an arithmetic number, because the mean of its divisors is an integer number (3945291768).

Almost surely, 2^20712781761 is an apocalyptic number.

20712781761 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20712781761 is a deficient number, since it is larger than the sum of its proper divisors (10849552383).

20712781761 is an equidigital number, since it uses as much as digits as its factorization.

20712781761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 986322951.

The product of its (nonzero) digits is 65856, while the sum is 42.

The spelling of 20712781761 in words is "twenty billion, seven hundred twelve million, seven hundred eighty-one thousand, seven hundred sixty-one".