21061407 has 16 divisors (see below), whose sum is σ = 28730880. Its totient is φ = 13719552.

The previous prime is 21061363. The next prime is 21061427. The reversal of 21061407 is 70416012.

It is not a de Polignac number, because 21061407 - 2⁶ = 21061343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21061427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45258 + ... + 45720.

It is an arithmetic number, because the mean of its divisors is an integer number (1795680).

Almost surely, 2^21061407 is an apocalyptic number.

21061407 is a deficient number, since it is larger than the sum of its proper divisors (7669473).

21061407 is a wasteful number, since it uses less digits than its factorization.

21061407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 782.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 21061407 is about 4589.2708571188. The cubic root of 21061407 is about 276.1610722273.

Adding to 21061407 its reverse (70416012), we get a palindrome (91477419).

The spelling of 21061407 in words is "twenty-one million, sixty-one thousand, four hundred seven".