3991651501 has 4 divisors (see below), whose sum is σ = 4099534012. Its totient is φ = 3883768992.

The previous prime is 3991651439. The next prime is 3991651511. The reversal of 3991651501 is 1051561993.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3603600900 + 388050601 = 60030^2 + 19699^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3991651501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991651511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53941200 + ... + 53941273.

It is an arithmetic number, because the mean of its divisors is an integer number (1024883503).

Almost surely, 2^3991651501 is an apocalyptic number.

It is an amenable number.

3991651501 is a deficient number, since it is larger than the sum of its proper divisors (107882511).

3991651501 is a wasteful number, since it uses less digits than its factorization.

3991651501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107882510.

The product of its (nonzero) digits is 36450, while the sum is 40.

The square root of 3991651501 is about 63179.5180497604. The cubic root of 3991651501 is about 1586.2959147502.

The spelling of 3991651501 in words is "three billion, nine hundred ninety-one million, six hundred fifty-one thousand, five hundred one".