1221420400 has 30 divisors (see below), whose sum is σ = 2934463472. Its totient is φ = 488568000.

The previous prime is 1221420397. The next prime is 1221420449. The reversal of 1221420400 is 40241221.

It is a Harshad number since it is a multiple of its sum of digits (16).

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, 1526376 + ... + 1527175.

Almost surely, 2^1221420400 is an apocalyptic number.

1221420400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221420400 is an abundant number, since it is smaller than the sum of its proper divisors (1713043072).

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

1221420400 is a wasteful number, since it uses less digits than its factorization.

1221420400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3053569 (or 3053558 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 1221420400 is about 34948.8254452135. The cubic root of 1221420400 is about 1068.9442522783.

Adding to 1221420400 its reverse (40241221), we get a palindrome (1261661621).

The spelling of 1221420400 in words is "one billion, two hundred twenty-one million, four hundred twenty thousand, four hundred".