721370087 has 4 divisors (see below), whose sum is σ = 723437400. Its totient is φ = 719302776.

The previous prime is 721370063. The next prime is 721370123. The reversal of 721370087 is 780073127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 780073127 = 97 ⋅8041991.

It is a cyclic number.

It is not a de Polignac number, because 721370087 - 2¹⁰ = 721369063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721370047) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1033133 + ... + 1033830.

It is an arithmetic number, because the mean of its divisors is an integer number (180859350).

Almost surely, 2^721370087 is an apocalyptic number.

721370087 is a deficient number, since it is larger than the sum of its proper divisors (2067313).

721370087 is a wasteful number, since it uses less digits than its factorization.

721370087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2067312.

The product of its (nonzero) digits is 16464, while the sum is 35.

The square root of 721370087 is about 26858.3336601510. Note that the first 3 decimals coincide. The cubic root of 721370087 is about 896.8490996774.

The spelling of 721370087 in words is "seven hundred twenty-one million, three hundred seventy thousand, eighty-seven".