1005661020 has 96 divisors (see below), whose sum is σ = 3465681408. Its totient is φ = 212182272.

The previous prime is 1005661009. The next prime is 1005661091. The reversal of 1005661020 is 201665001.

It is a happy number.

It is a super-2 number, since 2×1005661020² = 2022708174294880800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 86634 + ... + 97553.

It is an arithmetic number, because the mean of its divisors is an integer number (36100848).

Almost surely, 2^1005661020 is an apocalyptic number.

1005661020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1005661020 is an abundant number, since it is smaller than the sum of its proper divisors (2460020388).

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

1005661020 is a wasteful number, since it uses less digits than its factorization.

1005661020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184219 (or 184217 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 1005661020 is about 31712.1588669078. The cubic root of 1005661020 is about 1001.8834570292.

The spelling of 1005661020 in words is "one billion, five million, six hundred sixty-one thousand, twenty".