20861469 has 40 divisors (see below), whose sum is σ = 32931360. Its totient is φ = 13142304.

The previous prime is 20861459. The next prime is 20861509. The reversal of 20861469 is 96416802.

20861469 = 571² + 572² + ... + 628².

It is not a de Polignac number, because 20861469 - 2¹² = 20857373 is a prime.

It is a super-2 number, since 2×20861469² = 870401777675922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20861459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 194914 + ... + 195020.

It is an arithmetic number, because the mean of its divisors is an integer number (823284).

Almost surely, 2^20861469 is an apocalyptic number.

20861469 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

20861469 is the 2889-th heptagonal number.

It is an amenable number.

20861469 is a deficient number, since it is larger than the sum of its proper divisors (12069891).

20861469 is a wasteful number, since it uses less digits than its factorization.

20861469 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231 (or 222 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 20861469 is about 4567.4357138333. The cubic root of 20861469 is about 275.2844175866.

The spelling of 20861469 in words is "twenty million, eight hundred sixty-one thousand, four hundred sixty-nine".