1648658021 has 2 divisors, whose sum is σ = 1648658022. Its totient is φ = 1648658020.

The previous prime is 1648658017. The next prime is 1648658023. The reversal of 1648658021 is 1208568461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1399807396 + 248850625 = 37414^2 + 15775^2 .

It is a cyclic number.

It is not a de Polignac number, because 1648658021 - 2² = 1648658017 is a prime.

Together with 1648658023, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1648658021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1648658023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 824329010 + 824329011.

It is an arithmetic number, because the mean of its divisors is an integer number (824329011).

Almost surely, 2^1648658021 is an apocalyptic number.

It is an amenable number.

1648658021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1648658021 is an equidigital number, since it uses as much as digits as its factorization.

1648658021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 92160, while the sum is 41.

The square root of 1648658021 is about 40603.6700434825. The cubic root of 1648658021 is about 1181.3453058756.

The spelling of 1648658021 in words is "one billion, six hundred forty-eight million, six hundred fifty-eight thousand, twenty-one".