1625241661 has 4 divisors (see below), whose sum is σ = 1655906652. Its totient is φ = 1594576672.

The previous prime is 1625241659. The next prime is 1625241677. The reversal of 1625241661 is 1661425261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1661425261 = 7177 ⋅231493.

It can be written as a sum of positive squares in 2 ways, for example, as 686125636 + 939116025 = 26194^2 + 30645^2 .

It is a cyclic number.

It is not a de Polignac number, because 1625241661 - 2¹ = 1625241659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1625241691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15332416 + ... + 15332521.

It is an arithmetic number, because the mean of its divisors is an integer number (413976663).

Almost surely, 2^1625241661 is an apocalyptic number.

It is an amenable number.

1625241661 is a deficient number, since it is larger than the sum of its proper divisors (30664991).

1625241661 is an equidigital number, since it uses as much as digits as its factorization.

1625241661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30664990.

The product of its digits is 17280, while the sum is 34.

The square root of 1625241661 is about 40314.2860658601. The cubic root of 1625241661 is about 1175.7256205503.

The spelling of 1625241661 in words is "one billion, six hundred twenty-five million, two hundred forty-one thousand, six hundred sixty-one".