1215738421 has 2 divisors, whose sum is σ = 1215738422. Its totient is φ = 1215738420.

The previous prime is 1215738413. The next prime is 1215738431. The reversal of 1215738421 is 1248375121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 641608900 + 574129521 = 25330^2 + 23961^2 .

It is a cyclic number.

It is not a de Polignac number, because 1215738421 - 2³ = 1215738413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215738401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607869210 + 607869211.

It is an arithmetic number, because the mean of its divisors is an integer number (607869211).

Almost surely, 2^1215738421 is an apocalyptic number.

It is an amenable number.

1215738421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215738421 is an equidigital number, since it uses as much as digits as its factorization.

1215738421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 34.

The square root of 1215738421 is about 34867.4407004586. The cubic root of 1215738421 is about 1067.2841191499.

The spelling of 1215738421 in words is "one billion, two hundred fifteen million, seven hundred thirty-eight thousand, four hundred twenty-one".