721940026 has 4 divisors (see below), whose sum is σ = 1082910042. Its totient is φ = 360970012.

The previous prime is 721939993. The next prime is 721940033. The reversal of 721940026 is 620049127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 620049127 = 173 ⋅3584099.

It can be written as a sum of positive squares in only one way, i.e., 720868801 + 1071225 = 26849^2 + 1035^2 .

It is a super-2 number, since 2×721940026² = 1042394802281761352, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 721940026.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 180485005 + ... + 180485008.

Almost surely, 2^721940026 is an apocalyptic number.

721940026 is a deficient number, since it is larger than the sum of its proper divisors (360970016).

721940026 is a wasteful number, since it uses less digits than its factorization.

721940026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360970015.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 721940026 is about 26868.9416613308. The cubic root of 721940026 is about 897.0852312328.

The spelling of 721940026 in words is "seven hundred twenty-one million, nine hundred forty thousand, twenty-six".