721770451 has 4 divisors (see below), whose sum is σ = 731936304. Its totient is φ = 711604600.

The previous prime is 721770421. The next prime is 721770457. The reversal of 721770451 is 154077127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 154077127 = 43 ⋅3583189.

It is not a de Polignac number, because 721770451 - 2⁷ = 721770323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721770457) 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, 5082820 + ... + 5082961.

It is an arithmetic number, because the mean of its divisors is an integer number (182984076).

Almost surely, 2^721770451 is an apocalyptic number.

721770451 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

721770451 is a deficient number, since it is larger than the sum of its proper divisors (10165853).

721770451 is a wasteful number, since it uses less digits than its factorization.

721770451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10165852.

The product of its (nonzero) digits is 13720, while the sum is 34.

The square root of 721770451 is about 26865.7858809304. The cubic root of 721770451 is about 897.0149875677.

The spelling of 721770451 in words is "seven hundred twenty-one million, seven hundred seventy thousand, four hundred fifty-one".