628655431 has 4 divisors (see below), whose sum is σ = 632818864. Its totient is φ = 624492000.

The previous prime is 628655387. The next prime is 628655437. The reversal of 628655431 is 134556826.

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 628655431 - 2¹⁵ = 628622663 is a prime.

It is a super-2 number, since 2×628655431² = 790415301851591522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (628655437) 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, 2081490 + ... + 2081791.

It is an arithmetic number, because the mean of its divisors is an integer number (158204716).

Almost surely, 2^628655431 is an apocalyptic number.

628655431 is a deficient number, since it is larger than the sum of its proper divisors (4163433).

628655431 is a wasteful number, since it uses less digits than its factorization.

628655431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4163432.

The product of its digits is 172800, while the sum is 40.

The square root of 628655431 is about 25073.0020340605. The cubic root of 628655431 is about 856.6515873101.

The spelling of 628655431 in words is "six hundred twenty-eight million, six hundred fifty-five thousand, four hundred thirty-one".