1008728921 has 2 divisors, whose sum is σ = 1008728922. Its totient is φ = 1008728920.

The previous prime is 1008728887. The next prime is 1008728969. The reversal of 1008728921 is 1298278001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 625000000 + 383728921 = 25000^2 + 19589^2 .

It is a cyclic number.

It is not a de Polignac number, because 1008728921 - 2⁶ = 1008728857 is a prime.

It is not a weakly prime, because it can be changed into another prime (1008728821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 504364460 + 504364461.

It is an arithmetic number, because the mean of its divisors is an integer number (504364461).

Almost surely, 2^1008728921 is an apocalyptic number.

It is an amenable number.

1008728921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1008728921 is an equidigital number, since it uses as much as digits as its factorization.

1008728921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 1008728921 is about 31760.4930849633. The cubic root of 1008728921 is about 1002.9012151441.

The spelling of 1008728921 in words is "one billion, eight million, seven hundred twenty-eight thousand, nine hundred twenty-one".