16121961 has 6 divisors (see below), whose sum is σ = 23287290. Its totient is φ = 10747968.

The previous prime is 16121921. The next prime is 16121971. The reversal of 16121961 is 16912161.

It can be written as a sum of positive squares in only one way, i.e., 10361961 + 5760000 = 3219^2 + 2400^2 .

It is not a de Polignac number, because 16121961 - 2⁹ = 16121449 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16121921) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 895656 + ... + 895673.

It is an arithmetic number, because the mean of its divisors is an integer number (3881215).

Almost surely, 2^16121961 is an apocalyptic number.

It is an amenable number.

16121961 is a deficient number, since it is larger than the sum of its proper divisors (7165329).

16121961 is a wasteful number, since it uses less digits than its factorization.

16121961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1791335 (or 1791332 counting only the distinct ones).

The product of its digits is 648, while the sum is 27.

The square root of 16121961 is about 4015.2161834701. The cubic root of 16121961 is about 252.6228451682.

It can be divided in two parts, 161 and 21961, that added together give a palindrome (22122).

The spelling of 16121961 in words is "sixteen million, one hundred twenty-one thousand, nine hundred sixty-one".