1210155421 has 8 divisors (see below), whose sum is σ = 1285779960. Its totient is φ = 1138965184.

The previous prime is 1210155403. The next prime is 1210155451. The reversal of 1210155421 is 1245510121.

It can be written as a sum of positive squares in 4 ways, for example, as 86229796 + 1123925625 = 9286^2 + 33525^2 .

It is not a de Polignac number, because 1210155421 - 2⁹ = 1210154909 is a prime.

It is a super-2 number, since 2×1210155421² = 2928952285951374482, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1210155392 and 1210155401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1210155451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 118246 + ... + 128071.

It is an arithmetic number, because the mean of its divisors is an integer number (160722495).

Almost surely, 2^1210155421 is an apocalyptic number.

It is an amenable number.

1210155421 is a deficient number, since it is larger than the sum of its proper divisors (75624539).

1210155421 is an frugal number, since it uses more digits than its factorization.

1210155421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246368 (or 246334 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 22.

The square root of 1210155421 is about 34787.2882099194. The cubic root of 1210155421 is about 1065.6478593216.

Adding to 1210155421 its reverse (1245510121), we get a palindrome (2455665542).

The spelling of 1210155421 in words is "one billion, two hundred ten million, one hundred fifty-five thousand, four hundred twenty-one".