451521661 has 2 divisors, whose sum is σ = 451521662. Its totient is φ = 451521660.

The previous prime is 451521617. The next prime is 451521691. The reversal of 451521661 is 166125154.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 353214436 + 98307225 = 18794^2 + 9915^2 .

It is a cyclic number.

It is not a de Polignac number, because 451521661 - 2²¹ = 449424509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (451521601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 225760830 + 225760831.

It is an arithmetic number, because the mean of its divisors is an integer number (225760831).

Almost surely, 2^451521661 is an apocalyptic number.

It is an amenable number.

451521661 is a deficient number, since it is larger than the sum of its proper divisors (1).

451521661 is an equidigital number, since it uses as much as digits as its factorization.

451521661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7200, while the sum is 31.

The square root of 451521661 is about 21249.0390606258. The cubic root of 451521661 is about 767.1722111382.

The spelling of 451521661 in words is "four hundred fifty-one million, five hundred twenty-one thousand, six hundred sixty-one".