1901021 has 2 divisors, whose sum is σ = 1901022. Its totient is φ = 1901020.

The previous prime is 1900981. The next prime is 1901027. The reversal of 1901021 is 1201091.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1464100 + 436921 = 1210^2 + 661^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1901021 is a prime.

It is a super-2 number, since 2×1901021² = 7227761684882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1900987 and 1901005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1901027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 950510 + 950511.

It is an arithmetic number, because the mean of its divisors is an integer number (950511).

2^1901021 is an apocalyptic number.

It is an amenable number.

1901021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1901021 is an equidigital number, since it uses as much as digits as its factorization.

1901021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18, while the sum is 14.

The square root of 1901021 is about 1378.7751810937. The cubic root of 1901021 is about 123.8784144664.

The spelling of 1901021 in words is "one million, nine hundred one thousand, twenty-one".