1005665121 has 24 divisors (see below), whose sum is σ = 1469711360. Its totient is φ = 662600736.

The previous prime is 1005665113. The next prime is 1005665131. The reversal of 1005665121 is 1215665001.

It is a happy number.

1005665121 is a `hidden beast` number, since 1 + 0 + 0 + 5 + 6 + 651 + 2 + 1 = 666.

It is not a de Polignac number, because 1005665121 - 2³ = 1005665113 is a prime.

It is a super-2 number, since 2×1005665121² = 2022724671191889282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1005665131) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 321915 + ... + 325023.

Almost surely, 2^1005665121 is an apocalyptic number.

It is an amenable number.

1005665121 is a deficient number, since it is larger than the sum of its proper divisors (464046239).

1005665121 is a wasteful number, since it uses less digits than its factorization.

1005665121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3525 (or 3522 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 1005665121 is about 31712.2235265836. The cubic root of 1005665121 is about 1001.8848188924.

The spelling of 1005665121 in words is "one billion, five million, six hundred sixty-five thousand, one hundred twenty-one".