3655621820 has 12 divisors (see below), whose sum is σ = 7676805864. Its totient is φ = 1462248720.

The previous prime is 3655621807. The next prime is 3655621859. The reversal of 3655621820 is 281265563.

It is a super-2 number, since 2×3655621820² = 26727141781720224800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 91390526 + ... + 91390565.

It is an arithmetic number, because the mean of its divisors is an integer number (639733822).

Almost surely, 2^3655621820 is an apocalyptic number.

It is an amenable number.

3655621820 is an abundant number, since it is smaller than the sum of its proper divisors (4021184044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3655621820 is a wasteful number, since it uses less digits than its factorization.

3655621820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182781100 (or 182781098 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 38.

The square root of 3655621820 is about 60461.7384798022. The cubic root of 3655621820 is about 1540.4718040545.

The spelling of 3655621820 in words is "three billion, six hundred fifty-five million, six hundred twenty-one thousand, eight hundred twenty".