940638721 has 4 divisors (see below), whose sum is σ = 1026151344. Its totient is φ = 855126100.

The previous prime is 940638709. The next prime is 940638731. The reversal of 940638721 is 127836049.

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, and also an emirpimes, since its reverse is a distinct semiprime: 127836049 = 11 ⋅11621459.

It is a cyclic number.

It is not a de Polignac number, because 940638721 - 2¹³ = 940630529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (940638731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42756295 + ... + 42756316.

It is an arithmetic number, because the mean of its divisors is an integer number (256537836).

Almost surely, 2^940638721 is an apocalyptic number.

It is an amenable number.

940638721 is a deficient number, since it is larger than the sum of its proper divisors (85512623).

940638721 is a wasteful number, since it uses less digits than its factorization.

940638721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85512622.

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 940638721 is about 30669.8340556319. The cubic root of 940638721 is about 979.8079316083.

The spelling of 940638721 in words is "nine hundred forty million, six hundred thirty-eight thousand, seven hundred twenty-one".