1820542957 has 4 divisors (see below), whose sum is σ = 1821990240. Its totient is φ = 1819095676.

The previous prime is 1820542907. The next prime is 1820542963. The reversal of 1820542957 is 7592450281.

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 1820542957 - 2¹⁵ = 1820510189 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 (1820542907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 721753 + ... + 724270.

It is an arithmetic number, because the mean of its divisors is an integer number (455497560).

Almost surely, 2^1820542957 is an apocalyptic number.

It is an amenable number.

1820542957 is a deficient number, since it is larger than the sum of its proper divisors (1447283).

1820542957 is a wasteful number, since it uses less digits than its factorization.

1820542957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1447282.

The product of its (nonzero) digits is 201600, while the sum is 43.

The square root of 1820542957 is about 42667.8210950594. The cubic root of 1820542957 is about 1221.0505501346.

The spelling of 1820542957 in words is "one billion, eight hundred twenty million, five hundred forty-two thousand, nine hundred fifty-seven".