1221002021000 has 32 divisors (see below), whose sum is σ = 2857144731480. Its totient is φ = 488400808000.

The previous prime is 1221002020969. The next prime is 1221002021047. The reversal of 1221002021000 is 1202001221.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 93255722884 + 1127746298116 = 305378^2 + 1061954^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 610500011 + ... + 610502010.

Almost surely, 2^{1221002021000} is an apocalyptic number.

1221002021000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221002021000 is an abundant number, since it is smaller than the sum of its proper divisors (1636142710480).

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

1221002021000 is a wasteful number, since it uses less digits than its factorization.

1221002021000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1221002042 (or 1221002028 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 1221002021000 its reverse (1202001221), we get a palindrome (1222204022221).

The spelling of 1221002021000 in words is "one trillion, two hundred twenty-one billion, two million, twenty-one thousand".