1921531 has 2 divisors, whose sum is σ = 1921532. Its totient is φ = 1921530.

The previous prime is 1921529. The next prime is 1921537. The reversal of 1921531 is 1351291.

It is a weak prime.

It is an emirp because it is prime and its reverse (1351291) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1921531 - 2¹ = 1921529 is a prime.

It is a super-2 number, since 2×1921531² = 7384562767922, which contains 22 as substring.

Together with 1921529, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1921537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960765 + 960766.

It is an arithmetic number, because the mean of its divisors is an integer number (960766).

2^1921531 is an apocalyptic number.

1921531 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921531 is an equidigital number, since it uses as much as digits as its factorization.

1921531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 270, while the sum is 22.

The square root of 1921531 is about 1386.1929880071. The cubic root of 1921531 is about 124.3223273845.

The spelling of 1921531 in words is "one million, nine hundred twenty-one thousand, five hundred thirty-one".