21077739 has 20 divisors (see below), whose sum is σ = 33340824. Its totient is φ = 13224384.

The previous prime is 21077659. The next prime is 21077741. The reversal of 21077739 is 93777012.

It is not a de Polignac number, because 21077739 - 2¹² = 21073643 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21077759) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6277 + ... + 9030.

Almost surely, 2^21077739 is an apocalyptic number.

21077739 is a deficient number, since it is larger than the sum of its proper divisors (12263085).

21077739 is a wasteful number, since it uses less digits than its factorization.

21077739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15336 (or 15327 counting only the distinct ones).

The product of its (nonzero) digits is 18522, while the sum is 36.

The square root of 21077739 is about 4591.0498799294. The cubic root of 21077739 is about 276.2324365211.

The spelling of 21077739 in words is "twenty-one million, seventy-seven thousand, seven hundred thirty-nine".