20667261 has 4 divisors (see below), whose sum is σ = 27556352. Its totient is φ = 13778172.

The previous prime is 20667233. The next prime is 20667277. The reversal of 20667261 is 16276602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20667261 - 2⁶ = 20667197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20667211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3444541 + ... + 3444546.

It is an arithmetic number, because the mean of its divisors is an integer number (6889088).

Almost surely, 2^20667261 is an apocalyptic number.

It is an amenable number.

20667261 is a deficient number, since it is larger than the sum of its proper divisors (6889091).

20667261 is an equidigital number, since it uses as much as digits as its factorization.

20667261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6889090.

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 20667261 is about 4546.1259331435. The cubic root of 20667261 is about 274.4275076405.

The spelling of 20667261 in words is "twenty million, six hundred sixty-seven thousand, two hundred sixty-one".