20661011 has 4 divisors (see below), whose sum is σ = 23612592. Its totient is φ = 17709432.

The previous prime is 20660993. The next prime is 20661013. The reversal of 20661011 is 11016602.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20661011 - 2⁶ = 20660947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20661013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1475780 + ... + 1475793.

It is an arithmetic number, because the mean of its divisors is an integer number (5903148).

Almost surely, 2^20661011 is an apocalyptic number.

20661011 is a deficient number, since it is larger than the sum of its proper divisors (2951581).

20661011 is an equidigital number, since it uses as much as digits as its factorization.

20661011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2951580.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 20661011 is about 4545.4384826989. The cubic root of 20661011 is about 274.3998415838.

Adding to 20661011 its reverse (11016602), we get a palindrome (31677613).

The spelling of 20661011 in words is "twenty million, six hundred sixty-one thousand, eleven".