43720521 has 16 divisors (see below), whose sum is σ = 63370944. Its totient is φ = 26650944.

The previous prime is 43720511. The next prime is 43720529. The reversal of 43720521 is 12502734.

It is not a de Polignac number, because 43720521 - 2⁵ = 43720489 is a prime.

It is a super-2 number, since 2×43720521² = 3822967913022882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 43720491 and 43720500.

It is not an unprimeable number, because it can be changed into a prime (43720529) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1066 + ... + 9411.

It is an arithmetic number, because the mean of its divisors is an integer number (3960684).

Almost surely, 2^43720521 is an apocalyptic number.

It is an amenable number.

43720521 is a deficient number, since it is larger than the sum of its proper divisors (19650423).

43720521 is a wasteful number, since it uses less digits than its factorization.

43720521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10600.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 43720521 is about 6612.1494992173. The cubic root of 43720521 is about 352.2857769852.

The spelling of 43720521 in words is "forty-three million, seven hundred twenty thousand, five hundred twenty-one".