1628765221 has 16 divisors (see below), whose sum is σ = 1687891968. Its totient is φ = 1570665600.

The previous prime is 1628765183. The next prime is 1628765231. The reversal of 1628765221 is 1225678261.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1628765221 is a prime.

It is a super-2 number, since 2×1628765221² = 5305752290278357682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1628765231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2191776 + ... + 2192518.

It is an arithmetic number, because the mean of its divisors is an integer number (105493248).

Almost surely, 2^1628765221 is an apocalyptic number.

It is an amenable number.

1628765221 is a deficient number, since it is larger than the sum of its proper divisors (59126747).

1628765221 is a wasteful number, since it uses less digits than its factorization.

1628765221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1332.

The product of its digits is 80640, while the sum is 40.

The square root of 1628765221 is about 40357.9635388110. The cubic root of 1628765221 is about 1176.5746736720.

The spelling of 1628765221 in words is "one billion, six hundred twenty-eight million, seven hundred sixty-five thousand, two hundred twenty-one".