1555151965 has 4 divisors (see below), whose sum is σ = 1866182364. Its totient is φ = 1244121568.

The previous prime is 1555151947. The next prime is 1555151971. The reversal of 1555151965 is 5691515551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5691515551 = 109 ⋅52215739.

It can be written as a sum of positive squares in 2 ways, for example, as 1023296121 + 531855844 = 31989^2 + 23062^2 .

It is a cyclic number.

It is not a de Polignac number, because 1555151965 - 2¹¹ = 1555149917 is a prime.

It is a super-2 number, since 2×1555151965² = 4836995268486722450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155515192 + ... + 155515201.

It is an arithmetic number, because the mean of its divisors is an integer number (466545591).

Almost surely, 2^1555151965 is an apocalyptic number.

It is an amenable number.

1555151965 is a deficient number, since it is larger than the sum of its proper divisors (311030399).

1555151965 is an equidigital number, since it uses as much as digits as its factorization.

1555151965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311030398.

The product of its digits is 168750, while the sum is 43.

The square root of 1555151965 is about 39435.4151112930. The cubic root of 1555151965 is about 1158.5753330905.

The spelling of 1555151965 in words is "one billion, five hundred fifty-five million, one hundred fifty-one thousand, nine hundred sixty-five".