1547968921 has 2 divisors, whose sum is σ = 1547968922. Its totient is φ = 1547968920.

The previous prime is 1547968843. The next prime is 1547968927. The reversal of 1547968921 is 1298697451.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1547320896 + 648025 = 39336^2 + 805^2 .

It is a cyclic number.

It is not a de Polignac number, because 1547968921 - 2¹⁵ = 1547936153 is a prime.

It is not a weakly prime, because it can be changed into another prime (1547968927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 773984460 + 773984461.

It is an arithmetic number, because the mean of its divisors is an integer number (773984461).

Almost surely, 2^1547968921 is an apocalyptic number.

It is an amenable number.

1547968921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1547968921 is an equidigital number, since it uses as much as digits as its factorization.

1547968921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 52.

The square root of 1547968921 is about 39344.2361852407. The cubic root of 1547968921 is about 1156.7888102604.

The spelling of 1547968921 in words is "one billion, five hundred forty-seven million, nine hundred sixty-eight thousand, nine hundred twenty-one".