20661635 has 8 divisors (see below), whose sum is σ = 24840816. Its totient is φ = 16498080.

The previous prime is 20661631. The next prime is 20661643. The reversal of 20661635 is 53616602.

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

It is not a de Polignac number, because 20661635 - 2² = 20661631 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20661598 and 20661607.

It is not an unprimeable number, because it can be changed into a prime (20661631) 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, 764 + ... + 6473.

It is an arithmetic number, because the mean of its divisors is an integer number (3105102).

Almost surely, 2^20661635 is an apocalyptic number.

20661635 is a deficient number, since it is larger than the sum of its proper divisors (4179181).

20661635 is an equidigital number, since it uses as much as digits as its factorization.

20661635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7813.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 20661635 is about 4545.5071224232. The cubic root of 20661635 is about 274.4026040136.

The spelling of 20661635 in words is "twenty million, six hundred sixty-one thousand, six hundred thirty-five".