40991021 has 8 divisors (see below), whose sum is σ = 43346688. Its totient is φ = 38700000.

The previous prime is 40991009. The next prime is 40991047. The reversal of 40991021 is 12019904.

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

It is a cyclic number.

It is not a de Polignac number, because 40991021 - 2²² = 36796717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40991051) 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, 14855 + ... + 17396.

It is an arithmetic number, because the mean of its divisors is an integer number (5418336).

Almost surely, 2^40991021 is an apocalyptic number.

40991021 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

It is an amenable number.

40991021 is a deficient number, since it is larger than the sum of its proper divisors (2355667).

40991021 is a wasteful number, since it uses less digits than its factorization.

40991021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32323.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 40991021 is about 6402.4230569371. The cubic root of 40991021 is about 344.7965502146.

The spelling of 40991021 in words is "forty million, nine hundred ninety-one thousand, twenty-one".