128691650 has 12 divisors (see below), whose sum is σ = 239366562. Its totient is φ = 51476640.

The previous prime is 128691623. The next prime is 128691659. The reversal of 128691650 is 56196821.

It can be written as a sum of positive squares in 3 ways, for example, as 95433361 + 33258289 = 9769^2 + 5767^2 .

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (128691659) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1286867 + ... + 1286966.

Almost surely, 2^128691650 is an apocalyptic number.

128691650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

128691650 is a deficient number, since it is larger than the sum of its proper divisors (110674912).

128691650 is a wasteful number, since it uses less digits than its factorization.

128691650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2573845 (or 2573840 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 128691650 is about 11344.2342183155. The cubic root of 128691650 is about 504.8745236079.

The spelling of 128691650 in words is "one hundred twenty-eight million, six hundred ninety-one thousand, six hundred fifty".