29721421 has 4 divisors (see below), whose sum is σ = 29875612. Its totient is φ = 29567232.

The previous prime is 29721413. The next prime is 29721431. The reversal of 29721421 is 12412792.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15319396 + 14402025 = 3914^2 + 3795^2 .

It is a cyclic number.

It is not a de Polignac number, because 29721421 - 2³ = 29721413 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 29721421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (29721431) 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, 76806 + ... + 77191.

It is an arithmetic number, because the mean of its divisors is an integer number (7468903).

Almost surely, 2^29721421 is an apocalyptic number.

It is an amenable number.

29721421 is a deficient number, since it is larger than the sum of its proper divisors (154191).

29721421 is a wasteful number, since it uses less digits than its factorization.

29721421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154190.

The product of its digits is 2016, while the sum is 28.

The square root of 29721421 is about 5451.7355952027. The cubic root of 29721421 is about 309.7584695134.

The spelling of 29721421 in words is "twenty-nine million, seven hundred twenty-one thousand, four hundred twenty-one".