4021920865 has 4 divisors (see below), whose sum is σ = 4826305044. Its totient is φ = 3217536688.

The previous prime is 4021920863. The next prime is 4021920901. The reversal of 4021920865 is 5680291204.

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 1262309841 + 2759611024 = 35529^2 + 52532^2 .

It is a cyclic number.

It is not a de Polignac number, because 4021920865 - 2¹ = 4021920863 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4021920863) 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, 402192082 + ... + 402192091.

It is an arithmetic number, because the mean of its divisors is an integer number (1206576261).

Almost surely, 2^4021920865 is an apocalyptic number.

It is an amenable number.

4021920865 is a deficient number, since it is larger than the sum of its proper divisors (804384179).

4021920865 is an equidigital number, since it uses as much as digits as its factorization.

4021920865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804384178.

The product of its (nonzero) digits is 34560, while the sum is 37.

The square root of 4021920865 is about 63418.6160760387. The cubic root of 4021920865 is about 1590.2955379336.

The spelling of 4021920865 in words is "four billion, twenty-one million, nine hundred twenty thousand, eight hundred sixty-five".