20761905 has 16 divisors (see below), whose sum is σ = 33992640. Its totient is φ = 10815168.

The previous prime is 20761901. The next prime is 20761907. The reversal of 20761905 is 50916702.

It is not a de Polignac number, because 20761905 - 2² = 20761901 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20761901) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 15450 + ... + 16739.

It is an arithmetic number, because the mean of its divisors is an integer number (2124540).

Almost surely, 2^20761905 is an apocalyptic number.

It is an amenable number.

20761905 is a deficient number, since it is larger than the sum of its proper divisors (13230735).

20761905 is a wasteful number, since it uses less digits than its factorization.

20761905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32240.

The product of its (nonzero) digits is 3780, while the sum is 30.

The square root of 20761905 is about 4556.5233457100. The cubic root of 20761905 is about 274.8457757838.

The spelling of 20761905 in words is "twenty million, seven hundred sixty-one thousand, nine hundred five".