20340991251 has 12 divisors (see below), whose sum is σ = 33578779312. Its totient is φ = 11623423536.

The previous prime is 20340991247. The next prime is 20340991259. The reversal of 20340991251 is 15219904302.

It is not a de Polignac number, because 20340991251 - 2² = 20340991247 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20340991259) 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, 161436376 + ... + 161436501.

Almost surely, 2^20340991251 is an apocalyptic number.

20340991251 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20340991251 is a deficient number, since it is larger than the sum of its proper divisors (13237788061).

20340991251 is a wasteful number, since it uses less digits than its factorization.

20340991251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322872890 (or 322872887 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The spelling of 20340991251 in words is "twenty billion, three hundred forty million, nine hundred ninety-one thousand, two hundred fifty-one".