21077137509 has 16 divisors (see below), whose sum is σ = 29609428992. Its totient is φ = 13309998768.

The previous prime is 21077137481. The next prime is 21077137547. The reversal of 21077137509 is 90573177012.

It is a de Polignac number, because none of the positive numbers 2^k-21077137509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21077137559) 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, 1475737 + ... + 1489950.

It is an arithmetic number, because the mean of its divisors is an integer number (1850589312).

Almost surely, 2^21077137509 is an apocalyptic number.

It is an amenable number.

21077137509 is a deficient number, since it is larger than the sum of its proper divisors (8532291483).

21077137509 is a wasteful number, since it uses less digits than its factorization.

21077137509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2965816.

The product of its (nonzero) digits is 92610, while the sum is 42.

The spelling of 21077137509 in words is "twenty-one billion, seventy-seven million, one hundred thirty-seven thousand, five hundred nine".