1661632031261 has 8 divisors (see below), whose sum is σ = 1667674019424. Its totient is φ = 1655590355280.

The previous prime is 1661632031251. The next prime is 1661632031263. The reversal of 1661632031261 is 1621302361661.

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 1661632031261 - 2¹⁰ = 1661632030237 is a prime.

It is a super-2 number, since 2×1661632031261² (a number of 25 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 (1661632031263) 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, 19205846 + ... + 19292168.

It is an arithmetic number, because the mean of its divisors is an integer number (208459252428).

Almost surely, 2^{1661632031261} is an apocalyptic number.

It is an amenable number.

1661632031261 is a deficient number, since it is larger than the sum of its proper divisors (6041988163).

1661632031261 is an equidigital number, since it uses as much as digits as its factorization.

1661632031261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156091.

The product of its (nonzero) digits is 46656, while the sum is 38.

The spelling of 1661632031261 in words is "one trillion, six hundred sixty-one billion, six hundred thirty-two million, thirty-one thousand, two hundred sixty-one".