1642555261 has 4 divisors (see below), whose sum is σ = 1665056092. Its totient is φ = 1620054432.

The previous prime is 1642555241. The next prime is 1642555267. The reversal of 1642555261 is 1625552461.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1222551225 + 420004036 = 34965^2 + 20494^2 .

It is a cyclic number.

It is not a de Polignac number, because 1642555261 - 2⁷ = 1642555133 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1642555261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1642555267) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11250306 + ... + 11250451.

It is an arithmetic number, because the mean of its divisors is an integer number (416264023).

Almost surely, 2^1642555261 is an apocalyptic number.

It is an amenable number.

1642555261 is a deficient number, since it is larger than the sum of its proper divisors (22500831).

1642555261 is an equidigital number, since it uses as much as digits as its factorization.

1642555261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22500830.

The product of its digits is 72000, while the sum is 37.

The square root of 1642555261 is about 40528.4500197084. The cubic root of 1642555261 is about 1179.8858601175.

The spelling of 1642555261 in words is "one billion, six hundred forty-two million, five hundred fifty-five thousand, two hundred sixty-one".