21769957561 has 8 divisors (see below), whose sum is σ = 23787794304. Its totient is φ = 19758579120.

The previous prime is 21769957549. The next prime is 21769957609. The reversal of 21769957561 is 16575996712.

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 21769957561 - 2¹¹ = 21769955513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21769957496 and 21769957505.

It is not an unprimeable number, because it can be changed into a prime (21769957511) 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, 1607521 + ... + 1621006.

It is an arithmetic number, because the mean of its divisors is an integer number (2973474288).

Almost surely, 2^21769957561 is an apocalyptic number.

It is an amenable number.

21769957561 is a deficient number, since it is larger than the sum of its proper divisors (2017836743).

21769957561 is a wasteful number, since it uses less digits than its factorization.

21769957561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3229151.

The product of its digits is 7144200, while the sum is 58.

The spelling of 21769957561 in words is "twenty-one billion, seven hundred sixty-nine million, nine hundred fifty-seven thousand, five hundred sixty-one".