721989949 has 16 divisors (see below), whose sum is σ = 812116800. Its totient is φ = 637818624.

The previous prime is 721989943. The next prime is 721989977. The reversal of 721989949 is 949989127.

It is a cyclic number.

It is not a de Polignac number, because 721989949 - 2²³ = 713601341 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 721989893 and 721989902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721989943) 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, 24954 + ... + 45460.

It is an arithmetic number, because the mean of its divisors is an integer number (50757300).

Almost surely, 2^721989949 is an apocalyptic number.

It is an amenable number.

721989949 is a deficient number, since it is larger than the sum of its proper divisors (90126851).

721989949 is a wasteful number, since it uses less digits than its factorization.

721989949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20652.

The product of its digits is 2939328, while the sum is 58.

The square root of 721989949 is about 26869.8706546943. The cubic root of 721989949 is about 897.1059089217.

The spelling of 721989949 in words is "seven hundred twenty-one million, nine hundred eighty-nine thousand, nine hundred forty-nine".