161031780 has 384 divisors, whose sum is σ = 643507200. Its totient is φ = 32514048.

The previous prime is 161031779. The next prime is 161031781. The reversal of 161031780 is 87130161.

It is an interprime number because it is at equal distance from previous prime (161031779) and next prime (161031781).

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 (161031781) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1425004 + ... + 1425116.

It is an arithmetic number, because the mean of its divisors is an integer number (1675800).

Almost surely, 2^161031780 is an apocalyptic number.

161031780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161031780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (321753600).

161031780 is an abundant number, since it is smaller than the sum of its proper divisors (482475420).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161031780 is a wasteful number, since it uses less digits than its factorization.

161031780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180 (or 172 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 161031780 is about 12689.8297860925. The cubic root of 161031780 is about 544.0479746113.

The spelling of 161031780 in words is "one hundred sixty-one million, thirty-one thousand, seven hundred eighty".