21937429 has 8 divisors (see below), whose sum is σ = 23977728. Its totient is φ = 19980480.

The previous prime is 21937417. The next prime is 21937441. The reversal of 21937429 is 92473912.

It is an interprime number because it is at equal distance from previous prime (21937417) and next prime (21937441).

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

It is a cyclic number.

It is not a de Polignac number, because 21937429 - 2¹⁹ = 21413141 is a prime.

It is a super-2 number, since 2×21937429² = 962501582260082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21937499) 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, 20287 + ... + 21340.

It is an arithmetic number, because the mean of its divisors is an integer number (2997216).

Almost surely, 2^21937429 is an apocalyptic number.

It is an amenable number.

21937429 is a deficient number, since it is larger than the sum of its proper divisors (2040299).

21937429 is a wasteful number, since it uses less digits than its factorization.

21937429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41675.

The product of its digits is 27216, while the sum is 37.

The square root of 21937429 is about 4683.7409193934. The cubic root of 21937429 is about 279.9380347572.

It can be divided in two parts, 21937 and 429, that added together give a triangular number (22366 = T₂₁₁).

The spelling of 21937429 in words is "twenty-one million, nine hundred thirty-seven thousand, four hundred twenty-nine".