648181481 has 2 divisors, whose sum is σ = 648181482. Its totient is φ = 648181480.

The previous prime is 648181463. The next prime is 648181487. The reversal of 648181481 is 184181846.

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., 415344400 + 232837081 = 20380^2 + 15259^2 .

It is a cyclic number.

It is not a de Polignac number, because 648181481 - 2²² = 643987177 is a prime.

It is a super-2 number, since 2×648181481² = 840278464622706722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (648181487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324090740 + 324090741.

It is an arithmetic number, because the mean of its divisors is an integer number (324090741).

Almost surely, 2^648181481 is an apocalyptic number.

It is an amenable number.

648181481 is a deficient number, since it is larger than the sum of its proper divisors (1).

648181481 is an equidigital number, since it uses as much as digits as its factorization.

648181481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 49152, while the sum is 41.

The square root of 648181481 is about 25459.4084966639. The cubic root of 648181481 is about 865.4305188707.

The spelling of 648181481 in words is "six hundred forty-eight million, one hundred eighty-one thousand, four hundred eighty-one".