20278001 has 2 divisors, whose sum is σ = 20278002. Its totient is φ = 20278000.

The previous prime is 20277953. The next prime is 20278003. The reversal of 20278001 is 10087202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18835600 + 1442401 = 4340^2 + 1201^2 .

It is a cyclic number.

It is not a de Polignac number, because 20278001 - 2¹⁴ = 20261617 is a prime.

It is a super-2 number, since 2×20278001² = 822394649112002, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 20278003, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20278003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10139000 + 10139001.

It is an arithmetic number, because the mean of its divisors is an integer number (10139001).

Almost surely, 2^20278001 is an apocalyptic number.

It is an amenable number.

20278001 is a deficient number, since it is larger than the sum of its proper divisors (1).

20278001 is an equidigital number, since it uses as much as digits as its factorization.

20278001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 20278001 is about 4503.1101474425. The cubic root of 20278001 is about 272.6936636396.

The spelling of 20278001 in words is "twenty million, two hundred seventy-eight thousand, one".