647051621 has 2 divisors, whose sum is σ = 647051622. Its totient is φ = 647051620.

The previous prime is 647051609. The next prime is 647051723. The reversal of 647051621 is 126150746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 639837025 + 7214596 = 25295^2 + 2686^2 .

It is a cyclic number.

It is not a de Polignac number, because 647051621 - 2⁶ = 647051557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647051921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323525810 + 323525811.

It is an arithmetic number, because the mean of its divisors is an integer number (323525811).

Almost surely, 2^647051621 is an apocalyptic number.

It is an amenable number.

647051621 is a deficient number, since it is larger than the sum of its proper divisors (1).

647051621 is an equidigital number, since it uses as much as digits as its factorization.

647051621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 647051621 is about 25437.2093791752. The cubic root of 647051621 is about 864.9273758177.

The spelling of 647051621 in words is "six hundred forty-seven million, fifty-one thousand, six hundred twenty-one".