1916991225 has 72 divisors (see below), whose sum is σ = 3717157920. Its totient is φ = 968461920.

The previous prime is 1916991199. The next prime is 1916991233. The reversal of 1916991225 is 5221996191.

It is not a de Polignac number, because 1916991225 - 2⁸ = 1916990969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 239742 + ... + 247608.

Almost surely, 2^1916991225 is an apocalyptic number.

1916991225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1916991225 is a deficient number, since it is larger than the sum of its proper divisors (1800166695).

1916991225 is a wasteful number, since it uses less digits than its factorization.

1916991225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7924 (or 7894 counting only the distinct ones).

The product of its digits is 87480, while the sum is 45.

The square root of 1916991225 is about 43783.4583490158. The cubic root of 1916991225 is about 1242.2434293792.

The spelling of 1916991225 in words is "one billion, nine hundred sixteen million, nine hundred ninety-one thousand, two hundred twenty-five".