1821201012 has 18 divisors (see below), whose sum is σ = 4603591538. Its totient is φ = 607066992.

The previous prime is 1821201001. The next prime is 1821201071. The reversal of 1821201012 is 2101021281.

It can be written as a sum of positive squares in only one way, i.e., 1178274276 + 642926736 = 34326^2 + 25356^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×1821201012² = 6633546252219648288, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25294423 + ... + 25294494.

Almost surely, 2^1821201012 is an apocalyptic number.

1821201012 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1821201012 is an abundant number, since it is smaller than the sum of its proper divisors (2782390526).

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

1821201012 is a wasteful number, since it uses less digits than its factorization.

1821201012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50588927 (or 50588922 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 1821201012 is about 42675.5317717307. The cubic root of 1821201012 is about 1221.1976530676.

Adding to 1821201012 its reverse (2101021281), we get a palindrome (3922222293).

The spelling of 1821201012 in words is "one billion, eight hundred twenty-one million, two hundred one thousand, twelve".