1221212131 has 8 divisors (see below), whose sum is σ = 1252223424. Its totient is φ = 1190555520.

The previous prime is 1221212089. The next prime is 1221212143. The reversal of 1221212131 is 1312121221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221212131 - 2¹³ = 1221203939 is a prime.

It is a super-2 number, since 2×1221212131² = 2982718137803122322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221212191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81691 + ... + 95476.

It is an arithmetic number, because the mean of its divisors is an integer number (156527928).

Almost surely, 2^1221212131 is an apocalyptic number.

1221212131 is a deficient number, since it is larger than the sum of its proper divisors (31011293).

1221212131 is a wasteful number, since it uses less digits than its factorization.

1221212131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177341.

The product of its digits is 48, while the sum is 16.

The square root of 1221212131 is about 34945.8456901532. The cubic root of 1221212131 is about 1068.8834922524.

Adding to 1221212131 its reverse (1312121221), we get a palindrome (2533333352).

The spelling of 1221212131 in words is "one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred thirty-one".