1640520949 has 2 divisors, whose sum is σ = 1640520950. Its totient is φ = 1640520948.

The previous prime is 1640520943. The next prime is 1640521027. The reversal of 1640520949 is 9490250461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1634180625 + 6340324 = 40425^2 + 2518^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640520949 - 2³ = 1640520941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640520941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820260474 + 820260475.

It is an arithmetic number, because the mean of its divisors is an integer number (820260475).

Almost surely, 2^1640520949 is an apocalyptic number.

It is an amenable number.

1640520949 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640520949 is an equidigital number, since it uses as much as digits as its factorization.

1640520949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 40.

The square root of 1640520949 is about 40503.3449112539. The cubic root of 1640520949 is about 1179.3985609253.

The spelling of 1640520949 in words is "one billion, six hundred forty million, five hundred twenty thousand, nine hundred forty-nine".