1872421 has 2 divisors, whose sum is σ = 1872422. Its totient is φ = 1872420.

The previous prime is 1872419. The next prime is 1872427. The reversal of 1872421 is 1242781.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1464100 + 408321 = 1210^2 + 639^2 .

It is an emirp because it is prime and its reverse (1242781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1872421 - 2¹ = 1872419 is a prime.

Together with 1872419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1872427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 936210 + 936211.

It is an arithmetic number, because the mean of its divisors is an integer number (936211).

2^1872421 is an apocalyptic number.

It is an amenable number.

1872421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1872421 is an equidigital number, since it uses as much as digits as its factorization.

1872421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 896, while the sum is 25.

The square root of 1872421 is about 1368.3643520642. The cubic root of 1872421 is about 123.2540412336.

The spelling of 1872421 in words is "one million, eight hundred seventy-two thousand, four hundred twenty-one".