40721691 has 4 divisors (see below), whose sum is σ = 54295592. Its totient is φ = 27147792.

The previous prime is 40721689. The next prime is 40721699. The reversal of 40721691 is 19612704.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 40721691 - 2¹ = 40721689 is a prime.

It is a super-2 number, since 2×40721691² = 3316512235798962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40721699) 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, 6786946 + ... + 6786951.

It is an arithmetic number, because the mean of its divisors is an integer number (13573898).

Almost surely, 2^40721691 is an apocalyptic number.

40721691 is a deficient number, since it is larger than the sum of its proper divisors (13573901).

40721691 is a wasteful number, since it uses less digits than its factorization.

40721691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13573900.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 40721691 is about 6381.3549501654. The cubic root of 40721691 is about 344.0397325433.

The spelling of 40721691 in words is "forty million, seven hundred twenty-one thousand, six hundred ninety-one".