161621851 has 8 divisors (see below), whose sum is σ = 169979904. Its totient is φ = 153374760.

The previous prime is 161621819. The next prime is 161621881. The reversal of 161621851 is 158126161.

161621851 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 161621851 - 2⁵ = 161621819 is a prime.

It is a super-2 number, since 2×161621851² = 52243245441332402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161621881) 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, 24745 + ... + 30586.

It is an arithmetic number, because the mean of its divisors is an integer number (21247488).

Almost surely, 2^161621851 is an apocalyptic number.

161621851 is a deficient number, since it is larger than the sum of its proper divisors (8358053).

161621851 is a wasteful number, since it uses less digits than its factorization.

161621851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55481.

The product of its digits is 2880, while the sum is 31.

The square root of 161621851 is about 12713.0582866594. The cubic root of 161621851 is about 544.7116854520.

The spelling of 161621851 in words is "one hundred sixty-one million, six hundred twenty-one thousand, eight hundred fifty-one".