1321001000400 has 120 divisors (see below), whose sum is σ = 4480524638784. Its totient is φ = 331545344000.

The previous prime is 1321001000309. The next prime is 1321001000441. The reversal of 1321001000400 is 40001001231.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 32357076 + ... + 32397875.

Almost surely, 2^{1321001000400} is an apocalyptic number.

1321001000400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321001000400 is an abundant number, since it is smaller than the sum of its proper divisors (3159523638384).

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

1321001000400 is a wasteful number, since it uses less digits than its factorization.

1321001000400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64754989 (or 64754978 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 1321001000400 its reverse (40001001231), we get a palindrome (1361002001631).

The spelling of 1321001000400 in words is "one trillion, three hundred twenty-one billion, one million, four hundred", and thus it is an aban number.