20404961 has 2 divisors, whose sum is σ = 20404962. Its totient is φ = 20404960.

The previous prime is 20404957. The next prime is 20404987. The reversal of 20404961 is 16940402.

It is an a-pointer prime, because the next prime (20404987) can be obtained adding 20404961 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12390400 + 8014561 = 3520^2 + 2831^2 .

It is a cyclic number.

It is not a de Polignac number, because 20404961 - 2² = 20404957 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20404961.

It is not a weakly prime, because it can be changed into another prime (20404991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10202480 + 10202481.

It is an arithmetic number, because the mean of its divisors is an integer number (10202481).

Almost surely, 2^20404961 is an apocalyptic number.

It is an amenable number.

20404961 is a deficient number, since it is larger than the sum of its proper divisors (1).

20404961 is an equidigital number, since it uses as much as digits as its factorization.

20404961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 20404961 is about 4517.1850748005. The cubic root of 20404961 is about 273.2615891748.

The spelling of 20404961 in words is "twenty million, four hundred four thousand, nine hundred sixty-one".