1251220105 has 16 divisors (see below), whose sum is σ = 1528098624. Its totient is φ = 983263680.

The previous prime is 1251220099. The next prime is 1251220121. The reversal of 1251220105 is 5010221521.

It is not a de Polignac number, because 1251220105 - 2²⁷ = 1117002377 is a prime.

It is a super-2 number, since 2×1251220105² = 3131103502312422050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 274374 + ... + 278896.

It is an arithmetic number, because the mean of its divisors is an integer number (95506164).

Almost surely, 2^1251220105 is an apocalyptic number.

It is an amenable number.

1251220105 is a deficient number, since it is larger than the sum of its proper divisors (276878519).

1251220105 is an equidigital number, since it uses as much as digits as its factorization.

1251220105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5496.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 1251220105 is about 35372.5897412106. The cubic root of 1251220105 is about 1077.5677159152.

Adding to 1251220105 its reverse (5010221521), we get a palindrome (6261441626).

The spelling of 1251220105 in words is "one billion, two hundred fifty-one million, two hundred twenty thousand, one hundred five".