1617051721 has 2 divisors, whose sum is σ = 1617051722. Its totient is φ = 1617051720.

The previous prime is 1617051697. The next prime is 1617051727. The reversal of 1617051721 is 1271507161.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1295208121 + 321843600 = 35989^2 + 17940^2 .

It is an emirp because it is prime and its reverse (1271507161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1617051721 - 2⁹ = 1617051209 is a prime.

It is a super-2 number, since 2×1617051721² = 5229712536778123682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1617051727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 808525860 + 808525861.

It is an arithmetic number, because the mean of its divisors is an integer number (808525861).

Almost surely, 2^1617051721 is an apocalyptic number.

It is an amenable number.

1617051721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1617051721 is an equidigital number, since it uses as much as digits as its factorization.

1617051721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2940, while the sum is 31.

The square root of 1617051721 is about 40212.5816256554. The cubic root of 1617051721 is about 1173.7473830250.

Adding to 1617051721 its reverse (1271507161), we get a palindrome (2888558882).

The spelling of 1617051721 in words is "one billion, six hundred seventeen million, fifty-one thousand, seven hundred twenty-one".