1872721 has 2 divisors, whose sum is σ = 1872722. Its totient is φ = 1872720.

The previous prime is 1872713. The next prime is 1872727. The reversal of 1872721 is 1272781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1742400 + 130321 = 1320^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 1872721 - 2³ = 1872713 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

1872721 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1872721.

It is not a weakly prime, because it can be changed into another prime (1872727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 936360 + 936361.

It is an arithmetic number, because the mean of its divisors is an integer number (936361).

2^1872721 is an apocalyptic number.

It is an amenable number.

1872721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1872721 is an equidigital number, since it uses as much as digits as its factorization.

1872721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1568, while the sum is 28.

The square root of 1872721 is about 1368.4739676004. The cubic root of 1872721 is about 123.2606234851.

The spelling of 1872721 in words is "one million, eight hundred seventy-two thousand, seven hundred twenty-one".