721311634 has 4 divisors (see below), whose sum is σ = 1081967454. Its totient is φ = 360655816.

The previous prime is 721311589. The next prime is 721311637. The reversal of 721311634 is 436113127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 436113127 = 463 ⋅941929.

It can be written as a sum of positive squares in only one way, i.e., 466430409 + 254881225 = 21597^2 + 15965^2 .

It is not an unprimeable number, because it can be changed into a prime (721311637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 180327907 + ... + 180327910.

Almost surely, 2^721311634 is an apocalyptic number.

721311634 is a deficient number, since it is larger than the sum of its proper divisors (360655820).

721311634 is a wasteful number, since it uses less digits than its factorization.

721311634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360655819.

The product of its digits is 3024, while the sum is 28.

The square root of 721311634 is about 26857.2454656095. The cubic root of 721311634 is about 896.8248749706.

The spelling of 721311634 in words is "seven hundred twenty-one million, three hundred eleven thousand, six hundred thirty-four".