1902180997 has 4 divisors (see below), whose sum is σ = 1903322380. Its totient is φ = 1901039616.

The previous prime is 1902180979. The next prime is 1902181009. The reversal of 1902180997 is 7990812091.

It is a happy number.

It is a Cunningham number, because it is equal to 43614²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1014677316 + 887503681 = 31854^2 + 29791^2 .

It is a cyclic number.

It is not a de Polignac number, because 1902180997 - 2⁷ = 1902180869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1902180967) 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, 568188 + ... + 571525.

It is an arithmetic number, because the mean of its divisors is an integer number (475830595).

Almost surely, 2^1902180997 is an apocalyptic number.

It is an amenable number.

1902180997 is a deficient number, since it is larger than the sum of its proper divisors (1141383).

1902180997 is a wasteful number, since it uses less digits than its factorization.

1902180997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1141382.

The product of its (nonzero) digits is 81648, while the sum is 46.

The square root of 1902180997 is about 43614.0000114642. Note that the first 4 decimals coincide. The cubic root of 1902180997 is about 1239.0360608201.

The spelling of 1902180997 in words is "one billion, nine hundred two million, one hundred eighty thousand, nine hundred ninety-seven".