20661610 has 8 divisors (see below), whose sum is σ = 37190916. Its totient is φ = 8264640.

The previous prime is 20661587. The next prime is 20661631. The reversal of 20661610 is 1616602.

It can be written as a sum of positive squares in 2 ways, for example, as 20511841 + 149769 = 4529^2 + 387^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1033071 + ... + 1033090.

Almost surely, 2^20661610 is an apocalyptic number.

20661610 is a deficient number, since it is larger than the sum of its proper divisors (16529306).

20661610 is a wasteful number, since it uses less digits than its factorization.

20661610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2066168.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 20661610 is about 4545.5043724542. The cubic root of 20661610 is about 274.4024933404.

It can be divided in two parts, 206 and 61610, that added together give a palindrome (61816).

The spelling of 20661610 in words is "twenty million, six hundred sixty-one thousand, six hundred ten".