20661511 has 8 divisors (see below), whose sum is σ = 23559984. Its totient is φ = 17950080.

The previous prime is 20661463. The next prime is 20661523. The reversal of 20661511 is 11516602.

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 20661511 - 2¹⁵ = 20628743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661541) 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, 46525 + ... + 46966.

It is an arithmetic number, because the mean of its divisors is an integer number (2944998).

Almost surely, 2^20661511 is an apocalyptic number.

20661511 is a deficient number, since it is larger than the sum of its proper divisors (2898473).

20661511 is a wasteful number, since it uses less digits than its factorization.

20661511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93521.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 20661511 is about 4545.4934825605. The cubic root of 20661511 is about 274.4020550736.

The spelling of 20661511 in words is "twenty million, six hundred sixty-one thousand, five hundred eleven".