40157581661 has 4 divisors (see below), whose sum is σ = 40158267612. Its totient is φ = 40156895712.

The previous prime is 40157581649. The next prime is 40157581703. The reversal of 40157581661 is 16618575104.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10877238436 + 29280343225 = 104294^2 + 171115^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40157581661 is a prime.

It is a super-2 number, since 2×40157581661² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40157584661) 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, 246026 + ... + 375291.

It is an arithmetic number, because the mean of its divisors is an integer number (10039566903).

Almost surely, 2^40157581661 is an apocalyptic number.

It is an amenable number.

40157581661 is a deficient number, since it is larger than the sum of its proper divisors (685951).

40157581661 is an equidigital number, since it uses as much as digits as its factorization.

40157581661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685950.

The product of its (nonzero) digits is 201600, while the sum is 44.

The spelling of 40157581661 in words is "forty billion, one hundred fifty-seven million, five hundred eighty-one thousand, six hundred sixty-one".