1971138951 has 12 divisors (see below), whose sum is σ = 2864670328. Its totient is φ = 1306029744.

The previous prime is 1971138943. The next prime is 1971138973. The reversal of 1971138951 is 1598311791.

It is a happy number.

It is not a de Polignac number, because 1971138951 - 2³ = 1971138943 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1971138897 and 1971138906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1971138901) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 670360 + ... + 673293.

Almost surely, 2^1971138951 is an apocalyptic number.

1971138951 is a deficient number, since it is larger than the sum of its proper divisors (893531377).

1971138951 is a wasteful number, since it uses less digits than its factorization.

1971138951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1343822 (or 1343819 counting only the distinct ones).

The product of its digits is 68040, while the sum is 45.

The square root of 1971138951 is about 44397.5106396744. The cubic root of 1971138951 is about 1253.8312216092.

The spelling of 1971138951 in words is "one billion, nine hundred seventy-one million, one hundred thirty-eight thousand, nine hundred fifty-one".