1916921 has 2 divisors, whose sum is σ = 1916922. Its totient is φ = 1916920.

The previous prime is 1916917. The next prime is 1916939. The reversal of 1916921 is 1296191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1597696 + 319225 = 1264^2 + 565^2 .

It is a cyclic number.

It is not a de Polignac number, because 1916921 - 2² = 1916917 is a prime.

It is a super-2 number, since 2×1916921² = 7349172240482, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1916951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 958460 + 958461.

It is an arithmetic number, because the mean of its divisors is an integer number (958461).

2^1916921 is an apocalyptic number.

It is an amenable number.

1916921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1916921 is an equidigital number, since it uses as much as digits as its factorization.

1916921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 972, while the sum is 29.

The square root of 1916921 is about 1384.5291618453. The cubic root of 1916921 is about 124.2228260190. Note that the first 3 decimals are identical.

The spelling of 1916921 in words is "one million, nine hundred sixteen thousand, nine hundred twenty-one".