428640531 has 16 divisors (see below), whose sum is σ = 628034688. Its totient is φ = 257883200.

The previous prime is 428640497. The next prime is 428640539. The reversal of 428640531 is 135046824.

It is a cyclic number.

It is not a de Polignac number, because 428640531 - 2¹⁰ = 428639507 is a prime.

It is a super-2 number, since 2×428640531² = 367465409631923922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 428640492 and 428640501.

It is not an unprimeable number, because it can be changed into a prime (428640539) 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, 42885 + ... + 51926.

It is an arithmetic number, because the mean of its divisors is an integer number (39252168).

Almost surely, 2^428640531 is an apocalyptic number.

428640531 is a deficient number, since it is larger than the sum of its proper divisors (199394157).

428640531 is a wasteful number, since it uses less digits than its factorization.

428640531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94962.

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 428640531 is about 20703.6356952106. The cubic root of 428640531 is about 753.9879608619.

The spelling of 428640531 in words is "four hundred twenty-eight million, six hundred forty thousand, five hundred thirty-one".