2091656391 has 16 divisors (see below), whose sum is σ = 3052334208. Its totient is φ = 1263535200.

The previous prime is 2091656383. The next prime is 2091656423. The reversal of 2091656391 is 1936561902.

It is not a de Polignac number, because 2091656391 - 2³ = 2091656383 is a prime.

It is a super-2 number, since 2×2091656391² = 8750052916022289762, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2091656311) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93100 + ... + 113361.

It is an arithmetic number, because the mean of its divisors is an integer number (190770888).

Almost surely, 2^2091656391 is an apocalyptic number.

2091656391 is a deficient number, since it is larger than the sum of its proper divisors (960677817).

2091656391 is a wasteful number, since it uses less digits than its factorization.

2091656391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206782.

The product of its (nonzero) digits is 87480, while the sum is 42.

The square root of 2091656391 is about 45734.6301067364. The cubic root of 2091656391 is about 1278.8809374116.

The spelling of 2091656391 in words is "two billion, ninety-one million, six hundred fifty-six thousand, three hundred ninety-one".