1821997334 has 4 divisors (see below), whose sum is σ = 2732996004. Its totient is φ = 910998666.

The previous prime is 1821997273. The next prime is 1821997339. The reversal of 1821997334 is 4337991281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 4337991281 = 13 ⋅333691637.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821997339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 455499332 + ... + 455499335.

It is an arithmetic number, because the mean of its divisors is an integer number (683249001).

Almost surely, 2^1821997334 is an apocalyptic number.

1821997334 is a deficient number, since it is larger than the sum of its proper divisors (910998670).

1821997334 is an equidigital number, since it uses as much as digits as its factorization.

1821997334 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 910998669.

The product of its digits is 326592, while the sum is 47.

The square root of 1821997334 is about 42684.8607119667. The cubic root of 1821997334 is about 1221.3756171049.

The spelling of 1821997334 in words is "one billion, eight hundred twenty-one million, nine hundred ninety-seven thousand, three hundred thirty-four".