1221400131 has 16 divisors (see below), whose sum is σ = 1861707264. Its totient is φ = 697745664.

The previous prime is 1221400097. The next prime is 1221400153. The reversal of 1221400131 is 1310041221.

It is not a de Polignac number, because 1221400131 - 2⁶ = 1221400067 is a prime.

It is a super-2 number, since 2×1221400131² = 2983636560013634322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1221400131.

It is not an unprimeable number, because it can be changed into a prime (1221400231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 102570 + ... + 113856.

It is an arithmetic number, because the mean of its divisors is an integer number (116356704).

Almost surely, 2^1221400131 is an apocalyptic number.

1221400131 is a deficient number, since it is larger than the sum of its proper divisors (640307133).

1221400131 is a wasteful number, since it uses less digits than its factorization.

1221400131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16450.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1221400131 is about 34948.5354628774. The cubic root of 1221400131 is about 1068.9383393399.

Adding to 1221400131 its reverse (1310041221), we get a palindrome (2531441352).

The spelling of 1221400131 in words is "one billion, two hundred twenty-one million, four hundred thousand, one hundred thirty-one".