21690429 has 8 divisors (see below), whose sum is σ = 29328192. Its totient is φ = 14256480.

The previous prime is 21690413. The next prime is 21690451. The reversal of 21690429 is 92409612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21690429 - 2⁴ = 21690413 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21690429.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21690469) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50704 + ... + 51129.

It is an arithmetic number, because the mean of its divisors is an integer number (3666024).

Almost surely, 2^21690429 is an apocalyptic number.

It is an amenable number.

21690429 is a deficient number, since it is larger than the sum of its proper divisors (7637763).

21690429 is a wasteful number, since it uses less digits than its factorization.

21690429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101907.

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 21690429 is about 4657.2984658491. The cubic root of 21690429 is about 278.8834317317.

The spelling of 21690429 in words is "twenty-one million, six hundred ninety thousand, four hundred twenty-nine".