40070721 has 16 divisors (see below), whose sum is σ = 55540800. Its totient is φ = 25666368.

The previous prime is 40070713. The next prime is 40070729. The reversal of 40070721 is 12707004.

It is an interprime number because it is at equal distance from previous prime (40070713) and next prime (40070729).

It is not a de Polignac number, because 40070721 - 2³ = 40070713 is a prime.

It is a zygodrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (40070729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18735 + ... + 20763.

It is an arithmetic number, because the mean of its divisors is an integer number (3471300).

Almost surely, 2^40070721 is an apocalyptic number.

It is an amenable number.

40070721 is a deficient number, since it is larger than the sum of its proper divisors (15470079).

40070721 is a wasteful number, since it uses less digits than its factorization.

40070721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2288.

The product of its (nonzero) digits is 392, while the sum is 21.

The square root of 40070721 is about 6330.1438372283. The cubic root of 40070721 is about 342.1966226837.

Adding to 40070721 its reverse (12707004), we get a palindrome (52777725).

The spelling of 40070721 in words is "forty million, seventy thousand, seven hundred twenty-one".