20661401 has 2 divisors, whose sum is σ = 20661402. Its totient is φ = 20661400.

The previous prime is 20661397. The next prime is 20661419. The reversal of 20661401 is 10416602.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13104400 + 7557001 = 3620^2 + 2749^2 .

It is a cyclic number.

It is not a de Polignac number, because 20661401 - 2² = 20661397 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20661101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10330700 + 10330701.

It is an arithmetic number, because the mean of its divisors is an integer number (10330701).

Almost surely, 2^20661401 is an apocalyptic number.

It is an amenable number.

20661401 is a deficient number, since it is larger than the sum of its proper divisors (1).

20661401 is an equidigital number, since it uses as much as digits as its factorization.

20661401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 20661401 is about 4545.4813826480. The cubic root of 20661401 is about 274.4015681089.

The spelling of 20661401 in words is "twenty million, six hundred sixty-one thousand, four hundred one".