43720621 has 4 divisors (see below), whose sum is σ = 49966432. Its totient is φ = 37474812.

The previous prime is 43720619. The next prime is 43720657. The reversal of 43720621 is 12602734.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 43720621 - 2¹ = 43720619 is a prime.

It is a super-2 number, since 2×43720621² = 3822985401251282, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43724621) 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, 3122895 + ... + 3122908.

It is an arithmetic number, because the mean of its divisors is an integer number (12491608).

Almost surely, 2^43720621 is an apocalyptic number.

It is an amenable number.

43720621 is a deficient number, since it is larger than the sum of its proper divisors (6245811).

43720621 is an equidigital number, since it uses as much as digits as its factorization.

43720621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6245810.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 43720621 is about 6612.1570610505. The cubic root of 43720621 is about 352.2860455742.

The spelling of 43720621 in words is "forty-three million, seven hundred twenty thousand, six hundred twenty-one".