1906621 has 2 divisors, whose sum is σ = 1906622. Its totient is φ = 1906620.

The previous prime is 1906613. The next prime is 1906627. The reversal of 1906621 is 1266091.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1071225 + 835396 = 1035^2 + 914^2 .

It is an emirp because it is prime and its reverse (1266091) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1906621 - 2³ = 1906613 is a prime.

1906621 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1906627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 953310 + 953311.

It is an arithmetic number, because the mean of its divisors is an integer number (953311).

2^1906621 is an apocalyptic number.

It is an amenable number.

1906621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1906621 is an equidigital number, since it uses as much as digits as its factorization.

1906621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 1906621 is about 1380.8044756590. The cubic root of 1906621 is about 123.9999349635. Note that the first 4 decimals are identical.

The spelling of 1906621 in words is "one million, nine hundred six thousand, six hundred twenty-one".