3891391517890 has 32 divisors (see below), whose sum is σ = 7317782397360. Its totient is φ = 1488002208000.

The previous prime is 3891391517887. The next prime is 3891391517911. The reversal of 3891391517890 is 987151931983.

It can be written as a sum of positive squares in 8 ways, for example, as 1481529586761 + 2409861931129 = 1217181^2 + 1552373^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66399381 + ... + 66457960.

Almost surely, 2^{3891391517890} is an apocalyptic number.

3891391517890 is a deficient number, since it is larger than the sum of its proper divisors (3426390879470).

3891391517890 is a wasteful number, since it uses less digits than its factorization.

3891391517890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132857478.

The product of its (nonzero) digits is 14696640, while the sum is 64.

The spelling of 3891391517890 in words is "three trillion, eight hundred ninety-one billion, three hundred ninety-one million, five hundred seventeen thousand, eight hundred ninety".