718621981 has 8 divisors (see below), whose sum is σ = 895944384. Its totient is φ = 559965120.

The previous prime is 718621961. The next prime is 718621987. The reversal of 718621981 is 189126817.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 718621981 - 2⁵ = 718621949 is a prime.

It is a super-2 number, since 2×718621981² = 1032835103152728722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (718621987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4666300 + ... + 4666453.

It is an arithmetic number, because the mean of its divisors is an integer number (111993048).

Almost surely, 2^718621981 is an apocalyptic number.

It is an amenable number.

718621981 is a deficient number, since it is larger than the sum of its proper divisors (177322403).

718621981 is a wasteful number, since it uses less digits than its factorization.

718621981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9332771.

The product of its digits is 48384, while the sum is 43.

The square root of 718621981 is about 26807.1255639242. The cubic root of 718621981 is about 895.7087821955.

The spelling of 718621981 in words is "seven hundred eighteen million, six hundred twenty-one thousand, nine hundred eighty-one".