21142400309 has 4 divisors (see below), whose sum is σ = 22255158240. Its totient is φ = 20029642380.

The previous prime is 21142400299. The next prime is 21142400327. The reversal of 21142400309 is 90300424112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21142400309 - 2¹² = 21142396213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142400509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 556378937 + ... + 556378974.

It is an arithmetic number, because the mean of its divisors is an integer number (5563789560).

Almost surely, 2^21142400309 is an apocalyptic number.

It is an amenable number.

21142400309 is a deficient number, since it is larger than the sum of its proper divisors (1112757931).

21142400309 is a wasteful number, since it uses less digits than its factorization.

21142400309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1112757930.

The product of its (nonzero) digits is 1728, while the sum is 26.

The spelling of 21142400309 in words is "twenty-one billion, one hundred forty-two million, four hundred thousand, three hundred nine".