20752737761561 has 8 divisors (see below), whose sum is σ = 22359800703240. Its totient is φ = 19147203176832.

The previous prime is 20752737761531. The next prime is 20752737761597. The reversal of 20752737761561 is 16516773725702.

It can be written as a sum of positive squares in 4 ways, for example, as 5479929855625 + 15272807905936 = 2340925^2 + 3908044^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20752737761561 - 2²² = 20752733567257 is a prime.

It is a super-3 number, since 3×20752737761561³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 20752737761561.

It is not an unprimeable number, because it can be changed into a prime (20752737761531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 382061030 + ... + 382115343.

It is an arithmetic number, because the mean of its divisors is an integer number (2794975087905).

Almost surely, 2^{20752737761561} is an apocalyptic number.

It is an amenable number.

20752737761561 is a deficient number, since it is larger than the sum of its proper divisors (1607062941679).

20752737761561 is a wasteful number, since it uses less digits than its factorization.

20752737761561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 764178475.

The product of its (nonzero) digits is 25930800, while the sum is 59.

The spelling of 20752737761561 in words is "twenty trillion, seven hundred fifty-two billion, seven hundred thirty-seven million, seven hundred sixty-one thousand, five hundred sixty-one".