21037378 has 4 divisors (see below), whose sum is σ = 31556070. Its totient is φ = 10518688.

The previous prime is 21037369. The next prime is 21037409. The reversal of 21037378 is 87373012.

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

It can be written as a sum of positive squares in only one way, i.e., 21003889 + 33489 = 4583^2 + 183^2 .

It is a super-2 number, since 2×21037378² = 885142546229768, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5259343 + ... + 5259346.

Almost surely, 2^21037378 is an apocalyptic number.

21037378 is a deficient number, since it is larger than the sum of its proper divisors (10518692).

21037378 is a wasteful number, since it uses less digits than its factorization.

21037378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10518691.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 21037378 is about 4586.6521559848. The cubic root of 21037378 is about 276.0560080273.

The spelling of 21037378 in words is "twenty-one million, thirty-seven thousand, three hundred seventy-eight".