721993890454 has 8 divisors (see below), whose sum is σ = 1083126047688. Its totient is φ = 360951874560.

The previous prime is 721993890419. The next prime is 721993890481. The reversal of 721993890454 is 454098399127.

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

It is a super-2 number, since 2×721993890454² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 721993890392 and 721993890401.

It is a congruent number.

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 in 3 ways as a sum of consecutive naturals, for example, 22515307 + ... + 22547350.

It is an arithmetic number, because the mean of its divisors is an integer number (135390755961).

Almost surely, 2^721993890454 is an apocalyptic number.

721993890454 is a deficient number, since it is larger than the sum of its proper divisors (361132157234).

721993890454 is a wasteful number, since it uses less digits than its factorization.

721993890454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45070670.

The product of its (nonzero) digits is 19595520, while the sum is 61.

The spelling of 721993890454 in words is "seven hundred twenty-one billion, nine hundred ninety-three million, eight hundred ninety thousand, four hundred fifty-four".