1550128681 has 4 divisors (see below), whose sum is σ = 1600132864. Its totient is φ = 1500124500.

The previous prime is 1550128639. The next prime is 1550128711. The reversal of 1550128681 is 1868210551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1550128681 - 2⁷ = 1550128553 is a prime.

It is a super-2 number, since 2×1550128681² = 4805797855317599522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1550128681.

It is not an unprimeable number, because it can be changed into a prime (1550123681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25002045 + ... + 25002106.

It is an arithmetic number, because the mean of its divisors is an integer number (400033216).

Almost surely, 2^1550128681 is an apocalyptic number.

It is an amenable number.

1550128681 is a deficient number, since it is larger than the sum of its proper divisors (50004183).

1550128681 is an equidigital number, since it uses as much as digits as its factorization.

1550128681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50004182.

The product of its (nonzero) digits is 19200, while the sum is 37.

The square root of 1550128681 is about 39371.6735864758. The cubic root of 1550128681 is about 1157.3265525739.

The spelling of 1550128681 in words is "one billion, five hundred fifty million, one hundred twenty-eight thousand, six hundred eighty-one".