51969681 has 27 divisors (see below), whose sum is σ = 78836251. Its totient is φ = 34257168.

The previous prime is 51969679. The next prime is 51969683. The reversal of 51969681 is 18696915.

The square root of 51969681 is 7209.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (51969679) and next prime (51969683).

It can be written as a sum of positive squares in only one way, i.e., 9979281 + 41990400 = 3159^2 + 6480^2 .

It is a tau number, because it is divible by the number of its divisors (27).

It is not a de Polignac number, because 51969681 - 2¹ = 51969679 is a prime.

It is a super-2 number, since 2×51969681² = 5401695486483522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51969683) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 583885 + ... + 583973.

Almost surely, 2^51969681 is an apocalyptic number.

51969681 is the 7209-th square number.

51969681 is the 3605-th centered octagonal number.

It is an amenable number.

51969681 is a deficient number, since it is larger than the sum of its proper divisors (26866570).

51969681 is an frugal number, since it uses more digits than its factorization.

51969681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202 (or 92 counting only the distinct ones).

The product of its digits is 116640, while the sum is 45.

The cubic root of 51969681 is about 373.1785592670.

Adding to 51969681 its product of digits (116640), we get a triangular number (52086321 = T₁₀₂₀₆).

It can be divided in two parts, 51969 and 681, that added together give a triangular number (52650 = T₃₂₄).

The spelling of 51969681 in words is "fifty-one million, nine hundred sixty-nine thousand, six hundred eighty-one".