43861000021 has 8 divisors (see below), whose sum is σ = 45049488984. Its totient is φ = 42672672000.

The previous prime is 43861000019. The next prime is 43861000031. The reversal of 43861000021 is 12000016834.

43861000021 = 148089² + 148090².

It can be written as a sum of positive squares in 4 ways, for example, as 8474123025 + 35386876996 = 92055^2 + 188114^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 43861000021 - 2¹ = 43861000019 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 43861000021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43861000031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 688521 + ... + 749521.

It is an arithmetic number, because the mean of its divisors is an integer number (5631186123).

Almost surely, 2^43861000021 is an apocalyptic number.

43861000021 is the 148090-th centered square number.

It is an amenable number.

43861000021 is a deficient number, since it is larger than the sum of its proper divisors (1188488963).

43861000021 is a wasteful number, since it uses less digits than its factorization.

43861000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80471.

The product of its (nonzero) digits is 1152, while the sum is 25.

Adding to 43861000021 its reverse (12000016834), we get a palindrome (55861016855).

The spelling of 43861000021 in words is "forty-three billion, eight hundred sixty-one million, twenty-one", and thus it is an aban number.