40297721 has 8 divisors (see below), whose sum is σ = 40859424. Its totient is φ = 39739840.

The previous prime is 40297709. The next prime is 40297723. The reversal of 40297721 is 12779204.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 40297721 - 2⁶ = 40297657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40297723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24866 + ... + 26436.

It is an arithmetic number, because the mean of its divisors is an integer number (5107428).

Almost surely, 2^40297721 is an apocalyptic number.

It is an amenable number.

40297721 is a deficient number, since it is larger than the sum of its proper divisors (561703).

40297721 is a wasteful number, since it uses less digits than its factorization.

40297721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1911.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 40297721 is about 6348.0485977976. The cubic root of 40297721 is about 342.8415857938.

Adding to 40297721 its sum of digits (32), we get a triangular number (40297753 = T₈₉₇₇).

The spelling of 40297721 in words is "forty million, two hundred ninety-seven thousand, seven hundred twenty-one".