1657627661 has 2 divisors, whose sum is σ = 1657627662. Its totient is φ = 1657627660.

The previous prime is 1657627627. The next prime is 1657627669. The reversal of 1657627661 is 1667267561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1508934025 + 148693636 = 38845^2 + 12194^2 .

It is a cyclic number.

It is not a de Polignac number, because 1657627661 - 2¹⁸ = 1657365517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1657627669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828813830 + 828813831.

It is an arithmetic number, because the mean of its divisors is an integer number (828813831).

Almost surely, 2^1657627661 is an apocalyptic number.

It is an amenable number.

1657627661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1657627661 is an equidigital number, since it uses as much as digits as its factorization.

1657627661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 635040, while the sum is 47.

The square root of 1657627661 is about 40713.9737805093. The cubic root of 1657627661 is about 1183.4838297162.

The spelling of 1657627661 in words is "one billion, six hundred fifty-seven million, six hundred twenty-seven thousand, six hundred sixty-one".