620521609 has 2 divisors, whose sum is σ = 620521610. Its totient is φ = 620521608.

The previous prime is 620521597. The next prime is 620521633. The reversal of 620521609 is 906125026.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 328624384 + 291897225 = 18128^2 + 17085^2 .

It is a cyclic number.

It is not a de Polignac number, because 620521609 - 2¹³ = 620513417 is a prime.

It is not a weakly prime, because it can be changed into another prime (620521009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310260804 + 310260805.

It is an arithmetic number, because the mean of its divisors is an integer number (310260805).

Almost surely, 2^620521609 is an apocalyptic number.

It is an amenable number.

620521609 is a deficient number, since it is larger than the sum of its proper divisors (1).

620521609 is an equidigital number, since it uses as much as digits as its factorization.

620521609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 620521609 is about 24910.2711546864. The cubic root of 620521609 is about 852.9409587108.

The spelling of 620521609 in words is "six hundred twenty million, five hundred twenty-one thousand, six hundred nine".