516401621 has 4 divisors (see below), whose sum is σ = 517244652. Its totient is φ = 515558592.

The previous prime is 516401603. The next prime is 516401647. The reversal of 516401621 is 126104615.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 162435025 + 353966596 = 12745^2 + 18814^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-516401621 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 (516401671) 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, 420596 + ... + 421821.

It is an arithmetic number, because the mean of its divisors is an integer number (129311163).

Almost surely, 2^516401621 is an apocalyptic number.

It is an amenable number.

516401621 is a deficient number, since it is larger than the sum of its proper divisors (843031).

516401621 is an equidigital number, since it uses as much as digits as its factorization.

516401621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 843030.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 516401621 is about 22724.4718530486. The cubic root of 516401621 is about 802.2859726272.

The spelling of 516401621 in words is "five hundred sixteen million, four hundred one thousand, six hundred twenty-one".