4001155531 has 4 divisors (see below), whose sum is σ = 4002445600. Its totient is φ = 3999865464.

The previous prime is 4001155441. The next prime is 4001155537. The reversal of 4001155531 is 1355511004.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 4001155531 - 2⁹ = 4001155019 is a prime.

It is a super-2 number, since 2×4001155531² = 32018491166503783922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 4001155496 and 4001155505.

It is not an unprimeable number, because it can be changed into a prime (4001155537) 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, 640371 + ... + 646588.

It is an arithmetic number, because the mean of its divisors is an integer number (1000611400).

Almost surely, 2^4001155531 is an apocalyptic number.

4001155531 is a deficient number, since it is larger than the sum of its proper divisors (1290069).

4001155531 is a wasteful number, since it uses less digits than its factorization.

4001155531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1290068.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 4001155531 is about 63254.6878183744. The cubic root of 4001155531 is about 1587.5538948450.

Adding to 4001155531 its reverse (1355511004), we get a palindrome (5356666535).

The spelling of 4001155531 in words is "four billion, one million, one hundred fifty-five thousand, five hundred thirty-one".