1628668261 has 4 divisors (see below), whose sum is σ = 1776729024. Its totient is φ = 1480607500.

The previous prime is 1628668259. The next prime is 1628668267.

1628668261 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1628668261 - 2¹ = 1628668259 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 (1628668267) 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, 74030365 + ... + 74030386.

It is an arithmetic number, because the mean of its divisors is an integer number (444182256).

Almost surely, 2^1628668261 is an apocalyptic number.

1628668261 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1628668261 is a deficient number, since it is larger than the sum of its proper divisors (148060763).

1628668261 is a wasteful number, since it uses less digits than its factorization.

1628668261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148060762.

The product of its digits is 331776, while the sum is 46.

The square root of 1628668261 is about 40356.7622710247. The cubic root of 1628668261 is about 1176.5513261401.

The spelling of 1628668261 in words is "one billion, six hundred twenty-eight million, six hundred sixty-eight thousand, two hundred sixty-one".