1972721 has 2 divisors, whose sum is σ = 1972722. Its totient is φ = 1972720.

The previous prime is 1972717. The next prime is 1972739. The reversal of 1972721 is 1272791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1860496 + 112225 = 1364^2 + 335^2 .

It is a cyclic number.

It is not a de Polignac number, because 1972721 - 2² = 1972717 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1972741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 986360 + 986361.

It is an arithmetic number, because the mean of its divisors is an integer number (986361).

2^1972721 is an apocalyptic number.

It is an amenable number.

1972721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1972721 is an equidigital number, since it uses as much as digits as its factorization.

1972721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1764, while the sum is 29.

The square root of 1972721 is about 1404.5358663986. The cubic root of 1972721 is about 125.4166576283.

The spelling of 1972721 in words is "one million, nine hundred seventy-two thousand, seven hundred twenty-one".