1516909921 has 2 divisors, whose sum is σ = 1516909922. Its totient is φ = 1516909920.

The previous prime is 1516909907. The next prime is 1516909951. The reversal of 1516909921 is 1299096151.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 958769296 + 558140625 = 30964^2 + 23625^2 .

It is a cyclic number.

It is not a de Polignac number, because 1516909921 - 2¹⁷ = 1516778849 is a prime.

It is not a weakly prime, because it can be changed into another prime (1516909951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 758454960 + 758454961.

It is an arithmetic number, because the mean of its divisors is an integer number (758454961).

Almost surely, 2^1516909921 is an apocalyptic number.

It is an amenable number.

1516909921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1516909921 is an equidigital number, since it uses as much as digits as its factorization.

1516909921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43740, while the sum is 43.

The square root of 1516909921 is about 38947.5277906057. The cubic root of 1516909921 is about 1148.9997404435. Note that the first 3 decimals are identical.

The spelling of 1516909921 in words is "one billion, five hundred sixteen million, nine hundred nine thousand, nine hundred twenty-one".