20642515 has 8 divisors (see below), whose sum is σ = 25069968. Its totient is φ = 16314720.

The previous prime is 20642513. The next prime is 20642521. The reversal of 20642515 is 51524602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20642515 - 2¹ = 20642513 is a prime.

It is a super-2 number, since 2×20642515² = 852226851050450, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20642515.

It is not an unprimeable number, because it can be changed into a prime (20642513) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24456 + ... + 25285.

It is an arithmetic number, because the mean of its divisors is an integer number (3133746).

Almost surely, 2^20642515 is an apocalyptic number.

20642515 is a deficient number, since it is larger than the sum of its proper divisors (4427453).

20642515 is an equidigital number, since it uses as much as digits as its factorization.

20642515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49829.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 20642515 is about 4543.4034599626. The cubic root of 20642515 is about 274.3179350608.

The spelling of 20642515 in words is "twenty million, six hundred forty-two thousand, five hundred fifteen".