1537721 has 2 divisors, whose sum is σ = 1537722. Its totient is φ = 1537720.

The previous prime is 1537709. The next prime is 1537729. The reversal of 1537721 is 1277351.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1537600 + 121 = 1240^2 + 11^2 .

It is a cyclic number.

It is not a de Polignac number, because 1537721 - 2¹⁴ = 1521337 is a prime.

It is not a weakly prime, because it can be changed into another prime (1537729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 768860 + 768861.

It is an arithmetic number, because the mean of its divisors is an integer number (768861).

2^1537721 is an apocalyptic number.

It is an amenable number.

1537721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1537721 is an equidigital number, since it uses as much as digits as its factorization.

1537721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1470, while the sum is 26.

The square root of 1537721 is about 1240.0487893627. The cubic root of 1537721 is about 115.4230417542.

The spelling of 1537721 in words is "one million, five hundred thirty-seven thousand, seven hundred twenty-one".