20661293 has 4 divisors (see below), whose sum is σ = 20682780. Its totient is φ = 20639808.

The previous prime is 20661287. The next prime is 20661299. The reversal of 20661293 is 39216602.

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

It is an interprime number because it is at equal distance from previous prime (20661287) and next prime (20661299).

It can be written as a sum of positive squares in 2 ways, for example, as 11437924 + 9223369 = 3382^2 + 3037^2 .

It is a cyclic number.

It is not a de Polignac number, because 20661293 - 2¹⁴ = 20644909 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 (20661299) 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, 9230 + ... + 11247.

It is an arithmetic number, because the mean of its divisors is an integer number (5170695).

Almost surely, 2^20661293 is an apocalyptic number.

It is an amenable number.

20661293 is a deficient number, since it is larger than the sum of its proper divisors (21487).

20661293 is a wasteful number, since it uses less digits than its factorization.

20661293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21486.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 20661293 is about 4545.4695027027. The cubic root of 20661293 is about 274.4010899964.

Adding to 20661293 its reverse (39216602), we get a palindrome (59877895).

The spelling of 20661293 in words is "twenty million, six hundred sixty-one thousand, two hundred ninety-three".