20749491 has 18 divisors (see below), whose sum is σ = 34865532. Its totient is φ = 11856600.

The previous prime is 20749457. The next prime is 20749493. The reversal of 20749491 is 19494702.

It is not a de Polignac number, because 20749491 - 2¹⁰ = 20748467 is a prime.

It is a super-3 number, since 3×20749491³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (20749493) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 23085 + ... + 23966.

It is an arithmetic number, because the mean of its divisors is an integer number (1936974).

Almost surely, 2^20749491 is an apocalyptic number.

20749491 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20749491 is a deficient number, since it is larger than the sum of its proper divisors (14116041).

20749491 is a wasteful number, since it uses less digits than its factorization.

20749491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47071 (or 47061 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 20749491 is about 4555.1609192212. The cubic root of 20749491 is about 274.7909860827.

The spelling of 20749491 in words is "twenty million, seven hundred forty-nine thousand, four hundred ninety-one".