31220236161 has 32 divisors (see below), whose sum is σ = 46641571200. Its totient is φ = 20639016000.

The previous prime is 31220236153. The next prime is 31220236169. The reversal of 31220236161 is 16163202213.

31220236161 is a `hidden beast` number, since 3 + 1 + 2 + 20 + 23 + 616 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (31220236153) and next prime (31220236169).

It is not a de Polignac number, because 31220236161 - 2³ = 31220236153 is a prime.

It is a super-2 number, since 2×31220236161² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (31220236169) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1541875 + ... + 1561991.

It is an arithmetic number, because the mean of its divisors is an integer number (1457549100).

Almost surely, 2^31220236161 is an apocalyptic number.

It is an amenable number.

31220236161 is a deficient number, since it is larger than the sum of its proper divisors (15421335039).

31220236161 is a wasteful number, since it uses less digits than its factorization.

31220236161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20606 (or 20600 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

Adding to 31220236161 its reverse (16163202213), we get a palindrome (47383438374).

The spelling of 31220236161 in words is "thirty-one billion, two hundred twenty million, two hundred thirty-six thousand, one hundred sixty-one".