631617509 has 4 divisors (see below), whose sum is σ = 641044704. Its totient is φ = 622190316.

The previous prime is 631617461. The next prime is 631617517. The reversal of 631617509 is 905716136.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 631617509 - 2¹² = 631613413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (631617409) 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, 4713497 + ... + 4713630.

It is an arithmetic number, because the mean of its divisors is an integer number (160261176).

Almost surely, 2^631617509 is an apocalyptic number.

It is an amenable number.

631617509 is a deficient number, since it is larger than the sum of its proper divisors (9427195).

631617509 is an equidigital number, since it uses as much as digits as its factorization.

631617509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9427194.

The product of its (nonzero) digits is 34020, while the sum is 38.

The square root of 631617509 is about 25132.0016910711. The cubic root of 631617509 is about 857.9949272779.

The spelling of 631617509 in words is "six hundred thirty-one million, six hundred seventeen thousand, five hundred nine".