1921001 has 4 divisors (see below), whose sum is σ = 1932672. Its totient is φ = 1909332.

The previous prime is 1920991. The next prime is 1921013. The reversal of 1921001 is 1001291.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1921001 - 2¹⁸ = 1658857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1921021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5585 + ... + 5918.

It is an arithmetic number, because the mean of its divisors is an integer number (483168).

2^1921001 is an apocalyptic number.

It is an amenable number.

1921001 is a deficient number, since it is larger than the sum of its proper divisors (11671).

1921001 is a wasteful number, since it uses less digits than its factorization.

1921001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11670.

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

The square root of 1921001 is about 1386.0018037506. The cubic root of 1921001 is about 124.3108960671.

Adding to 1921001 its reverse (1001291), we get a palindrome (2922292).

The spelling of 1921001 in words is "one million, nine hundred twenty-one thousand, one".