21007077 has 16 divisors (see below), whose sum is σ = 34473600. Its totient is φ = 11080512.

The previous prime is 21007069. The next prime is 21007099. The reversal of 21007077 is 77070012.

It is not a de Polignac number, because 21007077 - 2³ = 21007069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21007067) 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, 38202 + ... + 38747.

It is an arithmetic number, because the mean of its divisors is an integer number (2154600).

Almost surely, 2^21007077 is an apocalyptic number.

It is an amenable number.

21007077 is a deficient number, since it is larger than the sum of its proper divisors (13466523).

21007077 is a wasteful number, since it uses less digits than its factorization.

21007077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76972.

The product of its (nonzero) digits is 686, while the sum is 24.

The square root of 21007077 is about 4583.3477939166. The cubic root of 21007077 is about 275.9234060723.

Adding to 21007077 its reverse (77070012), we get a palindrome (98077089).

The spelling of 21007077 in words is "twenty-one million, seven thousand, seventy-seven".