721123889 has 16 divisors (see below), whose sum is σ = 765600000. Its totient is φ = 678053376.

The previous prime is 721123877. The next prime is 721123913. The reversal of 721123889 is 988321127.

It is a cyclic number.

It is not a de Polignac number, because 721123889 - 2⁴ = 721123873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721123489) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 576737 + ... + 577985.

It is an arithmetic number, because the mean of its divisors is an integer number (47850000).

Almost surely, 2^721123889 is an apocalyptic number.

It is an amenable number.

721123889 is a deficient number, since it is larger than the sum of its proper divisors (44476111).

721123889 is a wasteful number, since it uses less digits than its factorization.

721123889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1784.

The product of its digits is 48384, while the sum is 41.

The square root of 721123889 is about 26853.7499988363. The cubic root of 721123889 is about 896.7470588605.

The spelling of 721123889 in words is "seven hundred twenty-one million, one hundred twenty-three thousand, eight hundred eighty-nine".