161221635 has 24 divisors (see below), whose sum is σ = 286269984. Its totient is φ = 83886720.

The previous prime is 161221603. The next prime is 161221667. The reversal of 161221635 is 536122161.

161221635 is a `hidden beast` number, since 1 + 6 + 1 + 2 + 21 + 635 = 666.

It is an interprime number because it is at equal distance from previous prime (161221603) and next prime (161221667).

It is not a de Polignac number, because 161221635 - 2⁵ = 161221603 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 161221599 and 161221608.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41847 + ... + 45536.

It is an arithmetic number, because the mean of its divisors is an integer number (11927916).

Almost surely, 2^161221635 is an apocalyptic number.

161221635 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

161221635 is a deficient number, since it is larger than the sum of its proper divisors (125048349).

161221635 is a wasteful number, since it uses less digits than its factorization.

161221635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87435 (or 87432 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 161221635 is about 12697.3081792953. The cubic root of 161221635 is about 544.2616998401.

Adding to 161221635 its reverse (536122161), we get a palindrome (697343796).

The spelling of 161221635 in words is "one hundred sixty-one million, two hundred twenty-one thousand, six hundred thirty-five".