1200100020 has 48 divisors (see below), whose sum is σ = 3840321408. Its totient is φ = 274308480.

The previous prime is 1200100019. The next prime is 1200100043. The reversal of 1200100020 is 200010021.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a junction number, because it is equal to n+sod(n) for n = 1200099981 and 1200100008.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1428271 + ... + 1429110.

It is an arithmetic number, because the mean of its divisors is an integer number (80006696).

Almost surely, 2^1200100020 is an apocalyptic number.

1200100020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1200100020 is an abundant number, since it is smaller than the sum of its proper divisors (2640221388).

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

1200100020 is a wasteful number, since it uses less digits than its factorization.

1200100020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2857400 (or 2857398 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 1200100020 is about 34642.4597856446. The cubic root of 1200100020 is about 1062.6880925596.

Adding to 1200100020 its reverse (200010021), we get a palindrome (1400110041).

The spelling of 1200100020 in words is "one billion, two hundred million, one hundred thousand, twenty".