1988715961 has 16 divisors (see below), whose sum is σ = 2042900496. Its totient is φ = 1935360000.

The previous prime is 1988715943. The next prime is 1988715983. The reversal of 1988715961 is 1695178891.

It can be written as a sum of positive squares in 8 ways, for example, as 194769936 + 1793946025 = 13956^2 + 42355^2 .

It is a 5-Lehmer number, since φ(1988715961) divides (1988715961-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 1988715961 - 2¹³ = 1988707769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1988715941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3102201 + ... + 3102841.

It is an arithmetic number, because the mean of its divisors is an integer number (127681281).

Almost surely, 2^1988715961 is an apocalyptic number.

1988715961 is the 19944-th centered decagonal number.

It is an amenable number.

1988715961 is a deficient number, since it is larger than the sum of its proper divisors (54184535).

1988715961 is a wasteful number, since it uses less digits than its factorization.

1988715961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1164.

The product of its digits is 1088640, while the sum is 55.

The square root of 1988715961 is about 44595.0217064641. The cubic root of 1988715961 is about 1257.5470799090.

The spelling of 1988715961 in words is "one billion, nine hundred eighty-eight million, seven hundred fifteen thousand, nine hundred sixty-one".