1098838721 has 2 divisors, whose sum is σ = 1098838722. Its totient is φ = 1098838720.

The previous prime is 1098838717. The next prime is 1098838751. The reversal of 1098838721 is 1278388901.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1098259600 + 579121 = 33140^2 + 761^2 .

It is an emirp because it is prime and its reverse (1278388901) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1098838721 - 2² = 1098838717 is a prime.

It is not a weakly prime, because it can be changed into another prime (1098838751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 549419360 + 549419361.

It is an arithmetic number, because the mean of its divisors is an integer number (549419361).

Almost surely, 2^1098838721 is an apocalyptic number.

It is an amenable number.

1098838721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1098838721 is an equidigital number, since it uses as much as digits as its factorization.

1098838721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 193536, while the sum is 47.

The square root of 1098838721 is about 33148.7363409226. The cubic root of 1098838721 is about 1031.9167253604.

The spelling of 1098838721 in words is "one billion, ninety-eight million, eight hundred thirty-eight thousand, seven hundred twenty-one".