161972550 has 72 divisors (see below), whose sum is σ = 445830840. Its totient is φ = 42134400.

The previous prime is 161972537. The next prime is 161972557. The reversal of 161972550 is 55279161.

161972550 is a `hidden beast` number, since 16 + 1 + 97 + 2 + 550 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161972557) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 14061 + ... + 22839.

It is an arithmetic number, because the mean of its divisors is an integer number (6192095).

Almost surely, 2^161972550 is an apocalyptic number.

161972550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 161972550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (222915420).

161972550 is an abundant number, since it is smaller than the sum of its proper divisors (283858290).

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

161972550 is a wasteful number, since it uses less digits than its factorization.

161972550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8838 (or 8830 counting only the distinct ones).

The product of its (nonzero) digits is 18900, while the sum is 36.

The square root of 161972550 is about 12726.8436778331. The cubic root of 161972550 is about 545.1053860115.

The spelling of 161972550 in words is "one hundred sixty-one million, nine hundred seventy-two thousand, five hundred fifty".