634534781 has 4 divisors (see below), whose sum is σ = 636117564. Its totient is φ = 632952000.

The previous prime is 634534729. The next prime is 634534801. The reversal of 634534781 is 187435436.

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 617969881 + 16564900 = 24859^2 + 4070^2 .

It is a cyclic number.

It is not a de Polignac number, because 634534781 - 2¹⁴ = 634518397 is a prime.

It is a super-2 number, since 2×634534781² = 805268776597435922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (634534711) 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, 790790 + ... + 791591.

It is an arithmetic number, because the mean of its divisors is an integer number (159029391).

Almost surely, 2^634534781 is an apocalyptic number.

It is an amenable number.

634534781 is a deficient number, since it is larger than the sum of its proper divisors (1582783).

634534781 is a wasteful number, since it uses less digits than its factorization.

634534781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1582782.

The product of its digits is 241920, while the sum is 41.

The square root of 634534781 is about 25189.9738189622. The cubic root of 634534781 is about 859.3138483182.

The spelling of 634534781 in words is "six hundred thirty-four million, five hundred thirty-four thousand, seven hundred eighty-one".