1821228961 has 8 divisors (see below), whose sum is σ = 1829689344. Its totient is φ = 1812788640.

The previous prime is 1821228947. The next prime is 1821229019. The reversal of 1821228961 is 1698221281.

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

It is a cyclic number.

It is not a de Polignac number, because 1821228961 - 2¹³ = 1821220769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1821228901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194980 + ... + 204106.

It is an arithmetic number, because the mean of its divisors is an integer number (228711168).

Almost surely, 2^1821228961 is an apocalyptic number.

It is an amenable number.

1821228961 is a deficient number, since it is larger than the sum of its proper divisors (8460383).

1821228961 is an equidigital number, since it uses as much as digits as its factorization.

1821228961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10031.

The product of its digits is 27648, while the sum is 40.

The square root of 1821228961 is about 42675.8592297800. The cubic root of 1821228961 is about 1221.2039000585.

The spelling of 1821228961 in words is "one billion, eight hundred twenty-one million, two hundred twenty-eight thousand, nine hundred sixty-one".