633720432721 has 4 divisors (see below), whose sum is σ = 670998105252. Its totient is φ = 596442760192.

The previous prime is 633720432701. The next prime is 633720432749. The reversal of 633720432721 is 127234027336.

It is a happy number.

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 224804946496 + 408915486225 = 474136^2 + 639465^2 .

It is a cyclic number.

It is not a de Polignac number, because 633720432721 - 2¹³ = 633720424529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (633720432701) 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, 18638836240 + ... + 18638836273.

It is an arithmetic number, because the mean of its divisors is an integer number (167749526313).

Almost surely, 2^633720432721 is an apocalyptic number.

It is an amenable number.

633720432721 is a deficient number, since it is larger than the sum of its proper divisors (37277672531).

633720432721 is a wasteful number, since it uses less digits than its factorization.

633720432721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37277672530.

The product of its (nonzero) digits is 254016, while the sum is 40.

The spelling of 633720432721 in words is "six hundred thirty-three billion, seven hundred twenty million, four hundred thirty-two thousand, seven hundred twenty-one".