1351865621 has 2 divisors, whose sum is σ = 1351865622. Its totient is φ = 1351865620.

The previous prime is 1351865573. The next prime is 1351865629. The reversal of 1351865621 is 1265681531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 754600900 + 597264721 = 27470^2 + 24439^2 .

It is a cyclic number.

It is not a de Polignac number, because 1351865621 - 2¹⁴ = 1351849237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1351865629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 675932810 + 675932811.

It is an arithmetic number, because the mean of its divisors is an integer number (675932811).

Almost surely, 2^1351865621 is an apocalyptic number.

It is an amenable number.

1351865621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1351865621 is an equidigital number, since it uses as much as digits as its factorization.

1351865621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 38.

The square root of 1351865621 is about 36767.7252627899. The cubic root of 1351865621 is about 1105.7183268459.

The spelling of 1351865621 in words is "one billion, three hundred fifty-one million, eight hundred sixty-five thousand, six hundred twenty-one".