1921449890 has 8 divisors (see below), whose sum is σ = 3458609820. Its totient is φ = 768579952.

The previous prime is 1921449857. The next prime is 1921449961. The reversal of 1921449890 is 989441291.

It can be written as a sum of positive squares in 2 ways, for example, as 1825938361 + 95511529 = 42731^2 + 9773^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96072485 + ... + 96072504.

Almost surely, 2^1921449890 is an apocalyptic number.

1921449890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1921449890 is a deficient number, since it is larger than the sum of its proper divisors (1537159930).

1921449890 is a wasteful number, since it uses less digits than its factorization.

1921449890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192144996.

The product of its (nonzero) digits is 186624, while the sum is 47.

The square root of 1921449890 is about 43834.3460085810. The cubic root of 1921449890 is about 1243.2057809782.

The spelling of 1921449890 in words is "one billion, nine hundred twenty-one million, four hundred forty-nine thousand, eight hundred ninety".