1921550369 has 2 divisors, whose sum is σ = 1921550370. Its totient is φ = 1921550368.

The previous prime is 1921550357. The next prime is 1921550437. The reversal of 1921550369 is 9630551291.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1199929600 + 721620769 = 34640^2 + 26863^2 .

It is a cyclic number.

It is not a de Polignac number, because 1921550369 - 2¹² = 1921546273 is a prime.

It is a super-2 number, since 2×1921550369² = 7384711641208072322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1921580369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960775184 + 960775185.

It is an arithmetic number, because the mean of its divisors is an integer number (960775185).

Almost surely, 2^1921550369 is an apocalyptic number.

It is an amenable number.

1921550369 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921550369 is an equidigital number, since it uses as much as digits as its factorization.

1921550369 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72900, while the sum is 41.

The square root of 1921550369 is about 43835.4921154080. The cubic root of 1921550369 is about 1243.2274510543.

The spelling of 1921550369 in words is "one billion, nine hundred twenty-one million, five hundred fifty thousand, three hundred sixty-nine".