20406929 has 4 divisors (see below), whose sum is σ = 20444784. Its totient is φ = 20369076.

The previous prime is 20406917. The next prime is 20406941. The reversal of 20406929 is 92960402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 92960402 = 2 ⋅46480201.

It is an interprime number because it is at equal distance from previous prime (20406917) and next prime (20406941).

It is a cyclic number.

It is not a de Polignac number, because 20406929 - 2¹⁶ = 20341393 is a prime.

It is a super-2 number, since 2×20406929² = 832885502422082, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20406895 and 20406904.

It is not an unprimeable number, because it can be changed into a prime (20406989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18107 + ... + 19200.

It is an arithmetic number, because the mean of its divisors is an integer number (5111196).

Almost surely, 2^20406929 is an apocalyptic number.

It is an amenable number.

20406929 is a deficient number, since it is larger than the sum of its proper divisors (37855).

20406929 is an equidigital number, since it uses as much as digits as its factorization.

20406929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37854.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 20406929 is about 4517.4029043246. The cubic root of 20406929 is about 273.2703739914.

The spelling of 20406929 in words is "twenty million, four hundred six thousand, nine hundred twenty-nine".